How can I fix the windows on Renault Megane Cabriolet?

The windows on my car have been giving trouble for more than 2 years. Was told about 2 months ago that Renault would cover the cost of replacement parts for the car. Contacted the Renault dealer who has taken over, I have now been told that they will only cover on a case by case situation, this is not what the other garage told me. The dealer near me have requested the mileage, the annual check up on the car, by an authorised Renault Dealer. Can't get this as the other garage was gone out of business.
More importantly, I want my car to be in working order, it cannot be used as a cabriolet as the system won't work unless the windows go down. Anyone else out there with the same problem? Have been told that it may be the regulators. Anyone know where I can get them? Tried to contact Renault Ireland, but keep being put onto the local dealer's website, which is useless to me. Does anyone have a phone number for Renault Ireland? I'm fed up with having to drive a car in the heat with windows that won't open and feel that this is also dangerous. I don't see why I have to pay for the repairs since it is a fault in the car itself and not one of my making.
Hope that someone can help me with this, I don't know too much about the workings of the window system, other than what I have been told by the local repair chap. Anyone got any ideas?