Pentagon FCU Credit Card Complaint

Pentagon FCU Credit card department,

Closing/Cancelling account Ohio

I opened a credit card ( ending in - ) with Penfed Credit Union on -/-/-, I was using this card for over two years without any problem. All of sudden, they closed my card without a notice until my transaction got declined when I was trying to pay at a gas station with this card a few days ago. Then I logged onto my account, the card disappeared on the page. I also check my credit report, it shows that the card -/-/-. I contacted their customer service to reopen the card, they did not give me any explanation and said they can not reopen a closed card, I can only go to apply a new card, then I submit an application, it got denied. I have never requested to close the card. And this is the SECOND time that they closed my account without notice!