Cant cancel

I habe been trying to cancel a number of unwanted contracts over the last year. Every time they phone you they promise a reduced fee with no extra added on months. The next account arrives and not only are things still the same, but they have added another 24 minths to your contract. Every time you upgrade they insist of giving you yet another number. This is ridiculous. When i say i dont want something because i have never used it i dont still want to keep it in case and no i dont want even more data on a number i have never used. Can the correct person help me to sort this issue out once and for all please? If you want to cancel something you didnt even do they want to charge you exgorbant fees to do it!!