Payment Issue

I made a payment to identity via Fnb but I used the wrong reference number.I phoned them and they gave me an email address and told me to email proof of payment with my account number and just say they must allocate the payment to this account.They send me a confirmation that they received my email.Now I get a sms every day stating that my account is in arrears with 2 payments.If this is how Identity works they can close my account and I wont recommend anyone to use them.