Citibank Credit Card Complaint

Citibank Credit card department,

Billing statement Pennsylvania

Citibank, failed to mail my -/-/- ( paper ) billing, never emailed or contacted me regarding nonpayment. I called, they said to pay the purchases of $300.00, which I electronic paid - day later. They would consider removing the $25.00 penalty and $4.00 - fee. They failed to remove, I called they claimed ca n't reverse the computer action. I become frustrated, decided to paid off the entire billing which amounted to $1000.00 which included later -/-/- purchases ( which included the penalty of $25.00 and interest. I mailed a letter of complaint on -/-/2016 filing my complaint in writing to Citi Card located in -, SD. They never responded, they again ignored my complaint. Now, checking on-line I see their latest billing statement of mine for the period of -/-/2016 to -/-/2016 a balance due of $9.00 for additional INTEREST charge dated -/-/2016. I PAID THE TOTAL BALANCE IN FULL WITH PENALTY AND INTEREST ON -/-/2016. THEY NOW BILLING ME $9.00 FOR INTEREST FEE DATED -/-/2016 AFTER PAYING THE BALANCE IN FULL. & lt ; This is totally unacceptable practice and illegal activity and I respectfully request a full investigation into Citi Card billing of interest on account after full payment. & gt ;