O2

Looking to take out 2nd line rental of iPhone 11. Is it possible to put £30 upfront cost on to next bill / account to pay when new bill generated?

Has anyone taken out a contract through Mobile Phones Direct and then cancelled almost immediately? I done this 2 weeks ago as I ordered wrong handset and they recalled it from DPD so I never received handset but O2 havent sent authorisation of disco...