rental car,com & europcar.com

Booked a hire car via rentalcars .com with europcar, I was given the various packages and chose the one that suited me and duly paid the £233 the full rental price quoted by rental car,com, when I collected the car at Manchester airport after a 20 hour flight from Cape Town was told the car was ready I signed the document and gave C/Card details for the rental deposit, returned the car 2 weeks late and found they chrged me another £420 for premium package & b/down cover !! Their customer service at europcar never even flinched or returned calls, just an email, as for rentalcars.com they never even returned an answer to my email, as we are pensioners thats a lot of money to be ********** for, be wary when dealing with either company.