Konica Minolta

I tried to put my printer c8000 under contract with Konica. 2 days later the service man come out to take a look at my printer. He said that my printer need some repair before they can consider if it is possible put it under contract, if not they still can service my printer and charge by labor. I am ok with all the repair cost and told the tech do what ever it need to be done. The tech came out for 3 times to fix the jam problem I have with my printer (it jam after 2000 – 3000 pages). Still they can not get the problem fix. The last time the tech came he damage my printer door, and told me that he would come back to fix it. He did come back and put my door back, but it just fall out 1 day after he leave.
The jam problem is still going on and I did pay over $ 1200 for part and labor. The tech made another appointment. At the appointment day he not show up, I tried to contact Konica many time. After 2 days the service manager call me back and told me my printer is damaged and they no longer want to service my printer anymore. I told him it fine but please come back and fix the door for me, because your tech damage it. He just hung up on me. 2 months later they send me the invoice of $ 1800 for their service on my c8000. I really mad and told them I don’t want to pay for the invoice because it is not fair. Your tech not finish the work on my machine, and also damage my printer and refuse to come back and fix it, and now you bill me.
I have to call another experience local tech to get my printer fix. He said that beside the door they damage there nothing wrong with your printer. He fix the jam problem by edit the air speed in the feeder, and clean some sensors. Since the service my printer worked fine without any problem. It had made over haft million print.