days on the phone with computers No ASSistance??? No Service

You cant speak to any human the email addresses don't work and their AI "Tobi" answer is sorry i cant assist as you are not a contract customer, which i am??? i only want to cancel one line but its impossible, i feel really sad as i did pay every month for yearssssssssss but i unfortunately have to let one contract go, but i still need the number on pay as you go, please can a human email me Urgently!