Sim swap

Have just upgraded my contract to a phone that uses a nano sim thus I was forced to do a sim swap what a mission! No one is willing to take the time to listen they just keep passing me on to a number that keeps asking me for my id the sim number then it cuts me off I have phoned them so many times I know the menu options off by hart. I eventually tried the ussd code option but the sim swap has not taken place and when I phone customer care they won't even listen to me.<br>