Damaged my vehicle

Took my car to them to replace my tyres and do alignment on car. After fitting the tyres and doing the alignment they somehow seemed to damage my car. My brakes wouldn't work and my calipers was rubbing up against the disk, causing it to scratch through the disk. Took it back to them the following morning to have it fixed. They are now telling me that whatever they have done was not the cause of the problem, tried telling them that the car was perfectly fine before they did alignment but they wouldn't listen. Now they expecting me to pay for the damages they have caused