unknown debit order

on the 27th I was debited an amount of R250 by old mutual reference number for the debit order omgpscheme ********** 6127

Today I received an sms from you '' Old Mutual Money Account referral received from your financial advisor. SMS Yes to 48719 and we'll call or visit a branch today https://goo.gl/kk9E5Z "

I've tried to call your offices several times but I'm kept on hold for a long time.

I want feedback I want to know why are you debiting my account without my authority. I'll be taking this matter further