You can only see outgoing calls on your bill so unless the incoming calls are on your phones call log, you cannot retrieve them.
I have no affiliation whatsoever with O2 or any subsidiary companies. Comments posted are entirely of my own opinion. This is not Customer Service so we are unable to help with account specific issues.
Hi there @Helpplease1976 welcome to our community. It would be great to hear back from you if you get a moment to pop back in, to see if the above advice from @MI5 and @Nick_selkent was helpful and if you have any additional questions the community could help you with?