Bad Customer Service

On the 29th October 2015 we hired a car through Europcar and returned the car on Tuesday 2nd November 2015 when we handed the car over we were advised everything was in order and could leave, a few minutes later i receive a phone call from them asking me to come back as they found a nail in the tyre yet everything was ok when we left the car back into their care. We could not return as we were boarding our flight back home and received numerous of calls pestering about this tyre how do we know for sure if the nail was not put inthere to make more money off us? a week later and still no refund made to us nor communication from the manager Javed or anyone from Europcar car. I called in yesterday 10 November on progress and after waiting 10 minutes on the line for Javed I was advised he was not in and put through another maanger by the name of Tanya who I explained my issue to who to0ok my details down and avised me the lady dealing with all their claims will call me back up until now i have not received no communication. We also forgot a personal item in the car and the lady who we handed over the car to who's name i cannot remember also advised me she had found the item and would