I am trying to upgrade my contract to the Pixel 10 pro as I have 15 days left of my contract, once I have the deal I want in my basket , I type my card details in and then press process and a message comes up sayin

 ' Error 

An unexpected error has occurred 

Oops something has gone wrong , please go back to the previous page and start again , if you continue to get this message , get in touch with us via our contact is page .

I tried it like 5 times yesterday and twice today and don't know what to do