Yes, the service of mitsubishi AC's is not good.
I am saying this on both behalf of my experience with an AC by Mitsubishi. I purchased an AC in November 2015 and at that time its service is really amazing at it was really great but after 4 months it stopped working then I talk to customer care and they tell me that repair will come at your home in 2 days but no one came than I went to Mitsubishi service center then owner told me to talk customer care and I told him all things but he didn't help me.
Then after I send a complaint e-mail to company than after technician came and repair the AC but I got too much problems due to their service and support.
Cooling power of AC is brilliant and everything is good but service and support is really bad.