8TA Data contract

I am wanting to give notice to cancel my data contract that I took out years ago. A week ago I went into the Cavendish store and completed the cancellation form. Today I got a sms on my personal mobile number giving me a case number and asking me to contact the call centre. Well, has anyone tried to call the 081180 number? I waited for for such a long time, that I put the phone on speaker to continue working till someone could answer my call. Eventually someone picked up and then asked me for the mobile number in question, my question is why did the promps ask me to punch in that number while I was waiting, what's the point if you are going to ask me for the number again? I then proceeded to give her the case number and said I wanted to give notice to cancel, the reply was that she can't cancel and this can only be done via telephone, but she couldn't put me through to that department and that I must wait for someone to call me, WHY? I have already completed the forms in store, why isn't there anyone in the call centre able to assist with a cancellation, why do I have to wait for someone to call me, why send me a sms to call you if you can't help me? (away 3-8 July)