Truworths refuses to remove my number from another account

Somebody else with my surname added my phone number to their account and I'm getting their SMS s about payments outstanding.

I visited the store to request that my number be removed, the manager Muzi said that it can't be done in store and I had to call the head office.

Another staff member assisted in calling on my behalf. He was told that the SMS did not come from Truworths, they said that I must now contact the company "PMNT" and that Truworths can not assist me.

I explained that PMNT probably stood for payment and that I just want my number removed from profiles that are not mine.

If this is not resolved soon, I will be cancelling my account and taking my business elsewhere.