Payflex cannot seem to change my old cell number to my new number.

How do I contact management via email as *** cannot seem to change my ****** cell number to my new cell number to be able to receive the OTP. Consultants reply in due course and I have verified my ID in three different ways via selfies on two different websites plus a selfie with me holding my RSA ID Doc and current date on printed A4 size paper to prove my identity and yet when logging in on Payflex account my old ****** cell number is still reflected and I cannot get the OTP to carry on with my transaction. This is going on now for nearly two weeks with different consultants. No one seems to be able to change my cell number. I urgently need assistance please. Thank you.