Micromax Informatics — Micromax a77 canvas juice touch is not responding at

My Micromax a77 canvas juice touch is not responding at all. It has been several days to this problem . I have switched it off and on several times but still it doesn't work . It works suddenly after 3-4 hour and only for a short time period like 5-6 minutes. But most ofthe time it remains unresponsive to touch. The screen doesn't respond to my touch. Please do something to repair my phone