Repair Scheem

I am with Teljoy for around 3 years with them. I always thought they provide excellent service.Untill I send in my one laptop in for repairs.The laptop was overheating and crashing every 5min.I log a repair with them.I received a call almost immediately.They said I have 2 options a on site repair or the courier will come and collect the laptop.I told them I want a on site repair. They confirm that the tech is available and be in contact with me .The next they a courier company came and collect it out of the blue.I few days later after the collection I receive a email from platinum stating I have tamper with the laptop and I will be liable for the repairs. I honestly don't know what scheme these guys are pulling but I hope Teljoy can resolve this matter as I have log it with there technical team.