We have been down the same road in the past for sure. Time and Time again. E-mail is a terrible strategy phone is always best. A great way to get a response is to text them if you have their mobile numbers. A great site for that is Twilio.com
Also What does your caller ID read ie when you call does it say "so and so debt services" perhaps changing the caller id with your telephone provider to something that does not look like a collection agency would be worth while. Also keep in mind when dealing with e-mail any mention of debt or financial help will often end up in spam or junk folders and never read. When leaving a message on their telephone its always a great idea to point that out to them that you will be e-mailing them and it may end iup in their spam/junk folder.

I hope that was helpful. Do you have a website?
Feel free to call for follow up if requires

That's tricky - you've been taking the right approach in trying different ways of connecting with the folks on your list, and testing out various types of content to engage them.

Since none of these have worked for you, I'd recommend a couple things to try:

1) Send a "break-up" email. If your audience is opening your emails but not clicking or engaging, it may be that they actually do want you to keep nagging them (about a problem as important as being in debt) but they don't want to bring themselves to do anything about it yet (it's a massive problem that it feels insurmountable to them). If you're willing to test the waters, send a friendly email along the lines of "We haven't heard from you in a while! We're guessing you've been busy, so we'll back off if you'd like. If you want to continue to receive emails from us, click here. Otherwise, we'll happily unsubscribe you, and hope you'll stay in touch through social media!" This will help you gauge how many folks actually are not interested vs. those who may need more (or different) nurturing before they'll convert.

2) Give them more valuable, free content designed to convert them. The best way to go about this is to send them free content without asking for anything in return (you already have their contact info anyway) so that you can provide tons of value. You mentioned informative videos - have you tried ebooks? Webinars? A free tool that helps them calculate how many months it'll take them to get out of debt? Once they engage with that free content, you'll have won more of their trust, and THEN you can pitch your product or service to them.

Happy to chat if you'd like to discuss more ideas. Best of luck!

I would suggest before you try any “tactics” which really are different marketing tools, you need to first understand your audience and have a strategy in place. You need to understand what their needs are (besides the obvious) and then figure out what pushes their buttons. Look at what your competitors are doing and understand what options your audience have and what messages are being broadcast to them.

Once you have a better understanding of your audience and their needs, then you can figure what tools are the best way to reach them and how (messaging).

Having the right tools but with the wrong message will not work. And having the right message and using the wrong tools to reach them will not work neither.

Bear with me; this leads somewhere.

Let's assume that your customers have some financial value to you. Even if you aim to help them reduce debt, that's still the case.

Prospects have a value below that of customers, since they won't all convert. And this particular set of prospects (which is converting at a minimal rate) has the least value.

But ... you expend a lot of resources trying to communicate with these people. If you can learn how to improve your process of reaching / converting the most difficult prospects, then you save wasted resources such as time; you'd gain more actual customers; and you'd improve your conversion rate long-term.

Even the hardest-to-reach prospects therefore have some value, which you can put a number on.

So my recommendation is to invest money to both entice them to respond and to learn why they weren't responding.

Offer a limited number of gift cards to anybody from this group who responds to a questionnaire or an interview. Make sure this is not a sales pitch. Emphasize that you're just trying to understand how to reach people better.

If they weren't responding before based on fear of dealing with their debt problem or because they were concerned about facing an aggressive sales pitch, then maybe a $5, $20, or $50 gift card just for speaking about why they weren't responding would tease them out of their silence.

It seems to me that someone with a debt problem might appreciate a no-pressure gift card. And you'd learn enough to improve the content or method of your followup.

Are you tracking any other metrics besides response rate in order to determine if they are engaging with the emails that you have sent? As others have recommended, the best idea would be to remove the email part from your strategy, at least until you get a better idea of why your emails aren't working.

Also depending on how long ago they subscribed to your list, you may just be better offer culling them from the list. After a certain time, it can incur more costs than it is worth to try to reactivate inactive email subscribers.

I'd be happy to discuss some options with you after I get a better idea of your sales funnel goals.