Rejected twice & no reason given

I have attempted to join zipcar twice within the past 2 years and have been rejected twice. This is really frustrating as I have not ever had any incidents and after generating a license check code from DVLA I have found no charges and my license comes out clean. However, I have been rejected membership once again and they refuse to discuss the reason. This is really disappointing as I have the benefit of the doing after my first refusal but this is unacceptable especially as they refuse to discuss the reason. I would not reccommend this company to anyone.