Citibank Credit Card Complaint

Citibank Credit card department,

Payoff process New Hampshire

I sent a check to pay my Citibank credit card bill in full, $13000.00 and the check was cashed on - - and cleared the bank account on -/-/-. As of today, - -, Citibank can not find the check and has not applied the amount to my account. After 5 calls from me and 5 calls from - - company, the company that sent the check, we have been stalled, asked to supply various details ( check number, account, etc. ) and have on multiple occasions with no resolution. Citibank hung up on me today when I called again for a follow up and answer to the issue of where my money is. This is unacceptable. They need to be able to find that check and respond in a courteous and professional manner. They are unwilling to call me in a proactive process and instructed me to just follow up in 72 hours for an update. NOT GOOD!