BMW 525D Odometer problem
 

Hello, i recently bought a car and i notice from first day that the battery is weak and needs to be replaced.
1 week ago i went on a website and put my reg. the number and bought the best battery ' most expensive ' in stock from the company 'Halfords '
then one of my friends told me that the battery needs to be programmed. so i paid for that as well.
Was on old guy who just replaces the battery not doing nothing else . he was claiming just the Models with Start-Stop needs.

My problem: So i got a BMW 525D from 2005 i had 151000 Milles and after replacing the battery shows 483638 Miles. i drive the car around and the miles from 483638 is increasing.
somebody recommend me that i should remove the plugs from the battery and leave it for a couple of hours. i did that . and every time when i unplug is going back to 483638 not increasing not decreasing any mile.
I have been to somebody with a tester as the car shows that needs service and he was trying to find out the problem but couldn't and when he try to remove the oil and other things from service was showing that should be done -3000000 miles ago and is not letting him to reset it .
Can somebody please help me out and tell me how to bring back that odometer? or i need to go to a BMW SPECIAL SERVICE ?