Product: Credit card or prepaid card

On XX/XX/2020, i purchased an air plane ticket from XXXX XXXX for a two way ticket ( going XXXX  to XXXX  on XX/XX/XXXX and returning from XXXX  to Miami on XX/XX/XXXX ) via my BANK OF AMERICA PERSONAL credit card for {$260.00}. 
This was around first week when XXXX was opened air travel during coronovirus epidemic During purchase process and on their website ( XXXX ) there was no information for any additional requirements. 
I also tried to reach them ( XXXX XXXX  ) on the phone to get information for any possible restriction/requirements for traveling to XXXX during coronovirus specially this first week XXXX government opens air traveling to the country, but i was not able to reach anyone on the phone. 
I heard from a traveling person ( to an other country ) that some countries are requiring Covid 19 test. 
I went to XXXX and got a Covid -19 test incase it might make my travel less complicated. 
When i try to fly on XX/XX/XXXX from XXXX aiport, I was told in check in desk that i can not fly not only without Covid 19 - PCS test. that time i found out test that i had was not PCR test. I noticed no one else was presenting COVID 19 test during check in nor any sign or information around check in area indicates test requirements. 
Later i learned this was because XXXX  citizen living in USA are not required to have a test. it seems to me because almost everyone flying that time was XXXX  citizen, airlines did not bother to post the covid19 test requirement information for others.

I was denied flight but offered cancellation of airplane or change of flight date within 3 days of original ticket.

Knowing i can not get Covid 19 PCR test very quick, i asked for cancellation. Person in check in said they can not cancel ticket at their computer but he will put my request in system but i have to reach their customer service on the phone to complete cancellation. He also said he is changing my flight for next day in case i did get Covid 19 pcr test. It made sense to me and i left the airport. In next several weeks i tried to reach XXXX XXXX via phone chat social media even called them their customer service in XXXX but they never got back to me in mails or voice messages. On their customer service phone number, in prerecording options they ask to press for different department if inquiry is for Cancellation/refunds. then no one is available only can leave voice message. after over 1 month not getting hold of anyone for refund i contacted my credit card company, BANK OF AMERICA.. About month later i received deny letter from the bank reads : " We understand you weren't satisfied with the quality of the service the merchant provided ; however the merchant has the right to request payment for any services that were rendered " problem is i was not rendered any services. Same like you order something online but you didnt receive then you contact merchant to report but they do not respond. what happens in that case? is this just because you are not happy with their quality of service I explained to bank of America again on the phone but they seem to listen then say they will forward information to proper department to investigate. i am not able to discuss this with a bank representative who is actually handling the issue themselves. it seems they are only filling a form on computer to forward an other department which is overs implied and does not represent details of the case. Time and afford i put in this worth a lot more than actual amount in question but i want bank to take proper step to resolve the issue so XXXX XXXX stop doing this to other customers. Below i attached some documents