3mobile mid-selling

Hi I need some advice please. In Dec 2008 I was in Ireland and I got a phone call on my mobile from 3mobile UK saying my contract was coming to an end and did I want to re-new it, I said no as I would be in Ireland for 6months minimum. The 3mobile salesman said I could use my phone in Ireland just as I had used it in the UK. (£20 month for free mins and texts) I came back to uk for Xmas etc and then returned to Ireland for 3 months , when I returned to the uk my bank account was overdrawn as 3mobile had taken a substantial amount of money out of my account. I rang them and said the contract was no use to me and they had mis-sold this to me. I then returned to Ireland and I never used my mobile again then I returned to uk in sept 2009 then in 2010 I recieved a bill from 3mobile for £450 approx. I called them and said i would like to go to court to ask a judge to decide if I owed any money . I heard nothing for a couple of years then a company called Lowells started sending me dept collecting letters for this money , I told them I did not owe this money then nothing for a while. Now I'm getting letters from Bryan Carter solicitors. I now feel harassed and fed up of these people and I want to go to small claims court to recover the money 3mobile took from my account and the bank charges I incurred because of them and to quash the dept they are asking for now. Iv asked them for my phone records prior to dec 2008 and the records of the new contract they sold me after Dec 2008. I also asked for a copy of the phone conversation I had with the 3mobile salesman in Dec2008. Do I have a case or am I being to optimistic

3mobile mid-selling