Tekton causing damage to my car.

Not even worth 1 star. Worst experience ever. Tekton took my car for repairs could not get the boot open because the key butten is not working. They then opende the boot somehow and after that the car battery wend dead becase the boot light was on for the duration of the repairs. When the car was picked up they acused us of having an old battery what was actualy +- 3 months old. They then jumped the car and after that the car brain went mad. The electrical of the car is not owrking and they are now saying it was like that because my husband added a speaker in the boot. That is totaly untrue and they refuse to pay. Please to not send your cars to them even with insurance because you will get bad service and might have to pay a lot of money to fix their faults.