A few buttons on my sony ericsson C905 have stopped working and they are essential :P The problem is:

It is an orange phone bought from dial-a-phone with dial a cover insurance!! who shall I ask for help?

Thank you in advance for replies!

As you say you 'bought' it, I assume that it's Pay as you Go?
If that's the case, all you need do is contact SE and speak to them. They may ask you to either send the phone in for repair, or take it to your nearest approved repair centre (which may be more convenient for you).

Sorry I don't have the number for them to hand, but google is your friend!

If the phone is bought from dial a phone and you have their insurance cover as you say in your OP,i would have thought your first port of call would be the number it gives on the insurance policy first.

As dial a phone do mostly contract phones i take it you bought a contract phone,if not even PAYG i would say if you have insurance cover on the phone, give them a call after all its what you took the cover out for.!!!!

Why pay for insurance cover and pay to get the phone fixed yourself?