Micromax — Handset hangs every time after slip time

Address:

Kutch, Gujarat

Dear sir, i bought canvas A311 in Jan 2015. It is not working propery since one month. After every half an hour when screen goes in slip mode, when we want to use, it do not displays. to start we have to switch off the handset and restart the system. Customer care has format the system but it is not working.Pls replace my handset.