Contract Cancellation

I called to cancel my pre-paid offers, as my contract ended last year and the airtime benefit continued. the lady that assisted me tried to give me an offer(which is her job and understand) which would cost less than I am currently paying. however, the main reason I am cancelling the current offer is because I no longer can afford the payment. she tried re-selling again which i repeatedly told her of my affordability status. she then went straight to say "your reference number is ***** " i asked am i supposed to write it down? she shouted with "Obviously " with anger, i was just so hurt on how she assumed i would find it an obvious thing to write it down. after reading out the reference number as i was about to ask about the debit orders' last date she hung up on me. I am still in shock and if it wasn't for the email confirmation i would still question myself if i will pay until August July ?june? when exactly.