New battery for SL500

If you live in Shreveport Louisiana the only Mercedes dealership is Holmes European Motors, they quoted me $480 for the rear battery! When I took my 2006 SL500 in for the B Service and they quoted to me that it would run around $495, but when I picked it up the bill was over $800. I could not any explanation as to why it was that much more, so I wrote the service manager via their website asking for justification for the large difference in the quote and actually bill. I have also called and asked to speak to the service manager, who is always busy or out. To this date I have not had any reply! The main reason I took it in was to find out why the ABC light kept coming on. They claim they could not check this out because by back battery was weak and needed replaced. Although it was stamped on the post 2-15 meaning it was under warranty but without paper receipt for the purchase of the battery, which came with the car when I purchased it, they would not be able to warranty it! Since they wanted over $400 I bought a battery elsewhere, upon replacing it I found that it was NOT the problem and that the battery I took out tested OK! Now I do not know who to trust to find out why the light comes on when starting it and then goes off?? One thing for sure the Mercedes Benz dealership in Shreveport does not offer any customer service or follow-up with customer concerns. I am very disappointed that I may have to drive all the way to Dallas to get professional service in the future. Also upon checking under the hood I found a number of issues, they left oil and fluids running on the motor, although they replaced the wipers, they left the window washer empty...other fluid levels were not checked because when I realize what inferior work they did, I checked everything before I was going out of town to find a number almost empty or very low! If anyone know a good reliable MB mechanic or specialty shop in the Shreveport, Louisiana area I can trust please let me know. I have a warranty on the car and I do not have to use Holmes European Motors according to them. I just need someone who can get approved by them.

Just a quick follow-up on the situation with the Holms European Dealership Service Dept. in Shreveport, La. This week after sending an email directly to Manager LUKE BRATLIE, who has just recently taken this position, I was contacted and he listened to all my concerns and complaints about the poor level of service I had received, after doing an investigation into the matter he contacted me a offered a partial refund. He was very professional and showed a great deal of concern about what had happened, he has assured me he is making it one of his goals to make the service depart top of the line in their procedure's and to be able to explain to every customer exactly what has been done to their car and justify the costs of doing any repairs. He wants complete customer satisfaction and he needs to be contacted directly if anyone feels they had not received the best care possible. We were very impressed with his sincere concern and the efforts he took to check out the situations related to the poor service we received. In todays market place businesses need to take more interest in taking care of their customers, responding quickly to any concerns and following up on making things right when they do go wrong. We feel he is working toward these goals and are going to give Holmes European Motors another opportunity to car for our SL500. If all goes well we will be thrilled, if not...you'll be hearing from us again! The Linns, Bossier City, La