Thanks for the advice. Orange have said it's been blacklisted Looks like i'm going to have to go back to the seller!!

Hi There, i was wondering if anyone could help me. i recently bought a phone off ebay (with box and charger etc). it worked for the first few days then stopped. The data services still work (bb pin, internet, emails etc) but the phone just says 'called failed' when i try to make a call. The network said it was the sim card and sent out a new one. I tried the new sim card and its still saying call failed. I'm worried its either locked (which i can fix) or blacklisted (which means it was reported lost or stolen). I called orange and they have record of the IMEI even though the phone is orange branded. I don't know how to check if the phone is blacklisted and i've contacted the seller and they are not responding. I've already left positive feedback and the transaction has gone through paypal as the phone was working for a few days (this makes me think that the seller has reported it lost or stolen to claim on the insurance) I'm unsure what i can do to get a refund as the phone is not working for me at all now and is useless. Its been longer than 45 days due to messing about trying to get a new sim card etc. Does anyone know if i can still contact either paypal or ebay to dispute the sale? i would appreciate any help! Thks Lisa