Telkom at it again

I have been a Telkom LTE subscriber for the past 4 years. I took out a new contract with Telkom LTE late last year. After many delays from inadequate systems and unprofessional staff to get the previous contracts deleted from my name. I know have been sent a message from a law firm requesting the recovery of R510.77 At no time was i contacted from any Telkom representative regarding this outstanding amount nor explained where this amount comes from. My contact details have not changed as i still receive their monthly statements of which shows nothing being in arrears. Please help ********** 072