Can I dispute a late payment?

Hi. I'm really annoyed and need some help please. I've been a customer of BMW's for over 4 years and have taken cars on personal lease contracts throughout this time. I have never ever missed a payment. My car went back on September 7th then I started a new 2 year agreement with another car again with BMW. Yesterday I got my monthly credit report and it has been slashed from 999 to 512, due to a late payment posted by BMW. I went ballistic and have since found out that this is an excess mileage charge relating to the car I returned on the 7th September. On speaking to BMW today they say they called me 3 times during September albeit to an old mobile number of mine and posted an invoice to my home address. I obviously did not get any of their calls and I did not get the invoice. I asked isn't it normal procedure to send out a reminder or a warning letter and they said no. Consequently they will not pull the late payment posting from my report and I now have to live with it until such times it fades out of the report. Is there no way I can contest this? I detested their flippant attitude on the phone to me, they didn't give a toss. If I didn't have an early termination fee on my new car I'd take it back and go elsewhere for a new car. I think it is disgraceful that they should treat a customer who has never missed a single payment before like this, and in particular when they were calling an old number of mine.....which they acknowledged when I gave them my correct number during the security check on the phone. Any help would be appreciated. Many Thanks