Drive Thru MOT

Had MOT done today at the Drive Thru MOT LTD St Albans….mechanic put the wrong milage down so that it was much higher than the milage shown on the vehicle.
When I queried this I was told that the number was so big no one would believe it and it would be ok.
Now we all know that when we try to sell our car that an inconcistant milage reading makes people suspicious of a vehicle and usually ends the prospect of a sale.
Their way of correcting this was to do another certificate with the correct milage...however it still showed the mistake...now it looks even worse and cannot be changed.
The managers way of dealing with this was to put a pen stroke through it. I asked then to sort this problem...I was shouted at, pushed in the chest, and then he tried to belittle me in front of his staff
When I asked him to fix the problem he just kept saying Oooo Ooooo He told me I was being aggressive. This is not true I merely wanted them to rectify the mistake that they made and then made again…
The DVLA have told me because of their lies and mistakes that I now have to live with it and nothing can be done.
The garage told me they could fix this problem and in 10 days I would have another MOT with the problem solved and the wrong milage number will disappear. This
is apparently another lie…since talking to the DVSA I have since discovered that this cannot be changed. Lied to again!
Could cost me thousands of pounds to the resale value of my vehicle