Service for the people?

So, for the last 6 years I have been paying around £30 a month for my phone contract on Three UK which for the most part has been good. However, I have found a better deal with another company and went into the Three store yesterday to cancel my contract.
After making this dedicated trip into town I was then told I could not cancel my contract in the store and could have to ring the Three number. This alone seems ridiculous to me considering they are able to create contracts and deal with customers but cannot cancel contracts with the people present?
So, I rang the Three UK number and was told without my father being present I could not cancel the contract, despite the fact that I was able to give all his details, I am over 18 and I was the one using the phone. Even when my father became present and spoke to the gentleman we were unable to cancel due to not having bank account details present.
I rang again this morning with everything present (including my dad) and spent 30 MINUTES of my morning on the phone explaining to four different staff that I just wanted to cancel my contract.
A simple, very easy procedure became very long and testing. I explained my reasons for leaving 7 times and they simply would not accept this.
I understand completely that they are a bushiness and aim to keep as many customers with them as possible. But making me repeat myself on numerous occasions and waste half an hour of my morning was certainly not going to change my mind.
Three UK repeat all the time how they are customer focused yet I have not seen this at all in the last few days.