Pathetic retail shop

Iv just made my first installment with identity last Sunday on 2nd of Dec, what annoys me is that during the whole week Iv been getting sms, calls that my account is overdue wereas I have paid, so have decided once to settle it and close it, it's useless and their pathetic system. You make a payment today at the store, tomorrow you get notifications, calls that they haven't received your payment, I dnt know if it's some kind of sick joke or what, I regret opening this account,.. What the ****!!