OTP sent to wrong number and nobody can help so I can't access funds

I am unable to use one of my bank cards due to the OTP being sent to the wrong number. Despite seeking online support 8 times since April and having them talk me through changing my telephone number at the ATM (and doing it correctly) the wrong number stubbornly remains in the system. Various phone calls end up with me being sent back to the ATM with my card to go through the process all over again. They won't believe me when I tell them that I am changing the contact number at the ATM, saving it, yet still the OTP is sent to the wrong number.