Best answer by Bumblebee
I'm going to ask some silly questions here - please forgive me but I do need to know in order to give you the correct answer.
Have you tried phoning OVO to find out where the problem lies?
They can be contacted on 0330 303 5063, they are well worth a chat to, it could well be the previous tenant/homeowner left debt on the account and records may not yet have been updated. Sadly many people move house and don't pay off their utilities.
If this is not the case please could you let me know, I promise to get back to you and see if I can help more, rest assured the phone call is a must and you get thru very quickly.
All the best hope to hear from you soon.