damage of KTM RC390 motorbike by service center

i went for the 1st free service of KTM RC390 at KTM Durgapur -713203, West Bengal i parked my motorcycle inside the service station premises and handed over the keys to the service station frontdesk who filled up the service form as well as my 1st free service coupon from the manual book as per their instructions. after filling up the form they advised me to wait in the waiting room. after around 45 minutes they called me and said that there was damage in my bike. i rushed to the bike and saw that the left mirror, the left handlebar, clutch lever and the gear shift lever were heavily damaged and broken. it seemed as if the bike had crashed or fallen off on its left side. i asked them how this happened. they said that they do not know anything about the matter and also claimed that i had crashed the bike prior to coming for service. this is an absolutely false and absurd claim. i denied their accuse. but they misbehaved with me and also threatened me that they will not provide me any service now or in future if i did not accept that the bike was crashed by me prior to service. i denied to accept that it was my fault. but they continued to behave very rudely with me.