Also, to return their kindless and considerationlessness, you should contact the state attorney general, the local bbb, and a few news stations (radio, tv, print media). Let them know about the kind and courteous service you’ve received. Mention fraud, bad service, being harassed by the members of the dealership, being put off, being over billed. Be sure to tell them this was to maintain you 15 year old car.
Then contact AMEX and explain to them that you were strong armed into paying for this amount. AMEX will refuse to pay the entire amount until the dealer settles. If the dealer is anything like the lame brains at the dealership I take my mbs to, your dealer will probably do absolutely nothing. And it will be months before you will be obligated to pay a cent. In the end you will get a deduction of the amount you claim in the dispute. Be sure to add a few hundred for the value of the detailing you were promised but did not receive. Be totally honest, and every bit as thoughtful as were the folks that took your money.
Do this and you will prevail.
'00 ML320 "Casper"
'92 400E "Stella"