Citibank Credit Card Complaint

Citibank Credit card department,

Closing/Cancelling account Arizona

AT & T Universal Card ( MasterCard ) cancelled our account without providing any notice on -/-/16, even though I used my card successfully on -/-/16 at - to place an order for about $50.00 ( Order Number # - ). I tired calling AT & T Universal Card to have the account reinstated but they said no, that we would have to re-apply. I have no problem doing so, but we should n't have to go through that. Account closures affect credit scores and thus I would appreciate your help to get this account reinstated.