pathetic customer service (old mutual )

every month on the 26th I get a debit from ommaxperls(OMMAXPERLS ********** ********** 325) for an amount of R666.00, I don't have an old mutual account, so I don't understand why I keep getting debited for this amount, I called the number that was left as "contact details" : ********** , to my amazement the number was invalid, its so frustrating to keep getting debited all the time for an account I don't have, its even worse when the debit order is reversed because it then shows as a reversal on my bank statement, hence the "credit record". I called the old mutual head office gave them the ref that's on my bank statement, but nothing picks up on their side, so how Is it possible that I'm getting debited for an amount of R666.00 every month but no 1 as an idea of what's going on, if this isn't unprofessional then I really don't know what is...please can someone contact me urgently regarding this issue, I know feel that this Is really getting out of hand. thank you !