HSBC North America Holdings Inc. Bank Account Or Service Complaint

HSBC North America Holdings Inc. Bank account or service department,

Checking account Deposits and withdrawals New York

I was charged by my bank HSBC a monthly amount of $20.00 from - 2015 to - 2015 without knowledge or authorization. When contacted the bank they refunded me $40.00 out of a total of $140.00. No explanation were given to me.