Old Mutual

I have a 10 year savings plan with Old Mutual for the past 4 years however now I have been double debited and I am told I signed a retirement saving with them with I haven't. I spoke to my financial advisor about it and she apologised saying that she was doing it to get paid for the December period however she forgot to cancel it.
I contacted the call centre and told them about it they said they require bank statement, copy of ID document and proof of residence from me in order for me to close the account that I never opened.
this is highly unprofessional and for a financial institution to do this? Can we now trust Old mutual with our money?

I am an unhappy customer and want nothing to do with old mutual ever again and want my problem to be sorted out cause this activity has created a lack of trust

I want a copy where it is said I signed for these documents :(