I'm on a non refresh plan too and can't get on live chat but then
someone from O2 rang to persuade me to stay and I queried it with them
apparently you have to ring support when you use the PAC code and they
will put a credit on your account to take ...
I want to leave O2 and email says with new charges coming into force I
can leave without termination charges so have requested a PAC code but
when this was texted back it said termination charges were £181