no customer care and incorrect ITC listing of customers

made a monthly installment payment and the 25th March via eft and send my proof of payment to *** for my payment to be allocated , i have made several attempts and communicated with them and i got respond that the payment needs to be allocated , now I'm harassed by the store for non payment getting sms and calls , that i missed a payment and this has also reflected on my ITC and this also will affect my ITC credit score ,