Business ProfileforTAP Air Portugal

My daughter needed to give up her passport to get a student ***** So we had to cancel our trip for three of us to Portugal. We are open to either a refund or credit/voucher for a future trip. The website allowed either option when cancelling and no warnings. Even thought we had discount tickets and didn't expect a full refund, a future flight option/credit would be fine with us. We would stand to lose about $5000. After several weeks, we called and per customer service's recommend, we filed a complaint. After that I ONLY RECEIVED PARTIAL CREDIT ($249.41 OF THE $5270.07). I WAS TOLD THAT THE **** WAS A DISCOUNTED FAIR. IF IT IS NOT ELIGIBLE FOR A CREDIT CARD REFUND, THEN I WOULD REQUEST A VOUCHER FOR A FLIGHT AT A LATER TIME, WHICH I PLAN TO MAKE.This was almost 2 months ago and I have not received much information on the status. Then after the complaint, I only receive a few small fees as shown above. When I look at the online status of the refund, some are complete, some have not even been opened. None of it makes sense.After several other attempts to contact someone that can help, they claim that it is against their terms and conditions based on my fare. ACTUALLY, it doesn't say they can't offer it either, there is no prohibiting of credits for future flights. I am open to something like a voucher. They are giving us the run around and hiding behind lengthy, hard to decipher terms, that actually don't preclude them from doing the right thing and keep a customer for now and the long term. They would rather take money with no service despite my willingness to keep using their service, perhaps not for long.I can provide further information upon request.