Help canceling insurance I haven’t had for 3 years

This year I am self employed and got insurance with BCBS through the market place. They are refusing to cover any of my bills because they say there’s a second insurance on file with Aetna. Aetna insurance is one I had from an employer 3 years ago and no other insurance companies I’ve had in that time have given me this issue (all through employers).

Steps I’ve taken so far:

Called blue BCBS and confirmed I only had one insurance. They said they’d call Aetna and resolve the issue. Issue was not resolved.

had a 3 way call with Aetna and BCBS to resolve old account information. Aetna said I had to submit paperwork to confirm my account was canceled bc it had been 3 years and they couldnt access my info. Obviously, bc it was terminated.

filled out form and tried to fax it however every fax number I tried did not work. Called Aetna and they gave me a few more numbers that also didn’t work. Only other option is to mail info. Lady on phone gave me an address on the phone with a 4 # zip code (zip codes have 5 numbers to my knowledge) that was different than the address on the form. I am skeptical considering none of their fax numbers worked.

asked former employer to also mail letter confirming termination of benefit. This was requested by the last person I spoke to at Aetna but not mentioned by the 3 other representatives I spoke to.

It feels like they are never going to cancel this insurance I don’t even have and medical bills that are covered by the insurance I pay for are going into collections.

Has anyone dealt with this before? How do I fix this?