Removing number from ex's account notifications

This is a complaint about Ekurhuleni Municipality in Springs . . . I keep getting an sms about my ex's account that is in arears for their family property & their whatsapp service is absolutely useless.

I just want to get my number removed from their notifications on arrears accounts.

Could ekurhuleni springs get back to me in order for me to provide the account number in question to remove my number ?