Other Car Rental Programs/Partners (ie. Alamo, Enterprise, Sixt) - Europcar - first Dollar, then National??

I reserved through Europcar, using the M & M Gold + Business Pkg. card access, for a 3 day reservation this month in Miami. When I booked online in December, I got an end price of $80 (March 8 - 11) and the instruction to pick up the car at the Dollar Counter at MIA. Today I just received a confirmation from Europcar saying the price is $140 and to pick up the car at National.

I called the German Europcar telephone number listed on the new confirmation and argued with them for quite a while. The answer was that the new supplier (presumably National?) will not honor the original price -- and they were certainly willing to cancel the reservation. I said absolutely not! (I also have a second reservation - also with the M&M card - at Avis which will cost about $110). Any suggestions as to whether I stand a chance of getting Dollar to honor the first reservation? Naturally I have a printout of the booking at $80.

Dear sir,

Thank you for bringing this to our attention. Europcar do guarantee the rate given at reservation time and even though there was a change of partnership and service provider for your car rental, your initial rate should be honored.
As you already have picked up your car please contact Europcar if the agreed rate was not applied for your rental.
We do apologise for any misleading information that have been given to you and look forward to serve you at one of our Europcar or National Car rental counters.

Best regards
Europcar International Reservation team

Years ago, Europcar and National used to be partners. Even had the same logo and fonts. About 10 years ago, Europcar was with Dollar while National went on its own. Now, Europcar and National are back together. I wish them a very prosperous marriage. My experience with Europcar has been consistently good.

We are having a bad experience with Europcar/Advantage in Toronto. We rented a car for one night for a total with tax of $46.88 CAD. Our March credit card statement reflected this charge.

On this month's statement there is an additional $31 charge. I had to call (long distance) 3 times and was put on hold repeatedly, and the person I spoke with pretended numerous times not to understand me.

She finally told me it was for "insurance" which we did not take, and refuses to fax me a copy of the contract she claims she has with us agreeing to this charge.

I am going to have to dispute it with the cc company, but what a pain! After having already spent who knows how much calling them.

Never again will I use them, that's for sure.