Online travel agency does not answer my messages about refunding my cancelled flights

I booked quite a few flights in 2020 that got cancelled because of the travel restrictions of the pandemic. The travel agency (quite a known one on the internet) had two options for the refund:

• faster refund – I would pay $20 or so and they would make process faster (up to 3 months)
• normal refund workflow – up to 6 months

I chose the faster refund and paid $20 more. The refund is still in process, but they do not answer me anymore to my messages.

I tried to be as friendly as possible, because I realize that we are going together through all this crazy time and I imagine that they had a lot of flights to get refunds from.

However, they do not answer me anymore to my messages at all. It has been about 20 months since the flights got cancelled, and about 6 months since they just don't answer me at all anymore.

I tried contacting the airlines directly and the result was:

• got a refund from company A
• got an ecredit from company B
• company C told me that only the travel agency can get the refund and not me directly
• company D told me to write an email to refunds@... and then I have not got any response anymore.

Is there anything I can do to make them answer my emails/calls?

Being old cancelled flights, they are not answering me via phone, but only a bot. They do not reply via email. At this point, I do not even care that much for the money (it would be nice to get it back), but I am a bit disapointed with the companies' behavior...