First Financial Bank credit card service Sioux City South Dakota

i have been paying this bill since 2005. the credit limit was 1250. many times i have been billed 2 x per month. if i did not pay that they would hit me with late fees. then they tried to cahnge the due date but failed to send the bill in a timely fashoin, causing the payment to be late, sometimes they would just cash my check after the due date. when the balance finally did come down, they managed to find a way to raise it up again by increasing the intrest rate. as of today i am once again over the limit, with a late fee, due to the date being altered again. when does it stop how do i make it stop. they have jinged my credit report and it sucks

Nancy
euclid, Ohio
U.S.A.