Sanlam send my confidential documents to a stranger's cellphone number

Sanlam changed my cellphone number without my knowledge ... I cannot even change it back because all OTP are going to a strange number that I do not recognise

I urgently need Sanlam to fix legal documents t ofind out where they sent my pension because according to them I withdrew it in December 2023 but I never received any payout

I cannot use any electronic assist because all OTP going to phone number that I do not know where they invented ... not getting a response from them nor are they fixing since I been with them November 2022 (it is now October 2024) ... When I call the customer / help line they say someone will call me or fix in 24 hours but after almost 2 years nothing is done ... and now pension is missing .. I suspect *****