Changing an email address problem

I'm trying to change my email address but the app edit function reverts back to the original

Contact lebara support

Yeah, tried them 3 times, I informed them the app doesn't let you change email addresses, they informed me they would do it from their end, all that happened was this morning they delinked me and suspended my payment method.

I've opted to change my communication preferences to SMS and un-ticked my email address, hopefully that'll limit further communication from Lebara to texts