Buggy android does not turn on

I got a Yu Yuphoria 5010. I had custom installed Marshmallow CyanogenMod a few months back. Recently, the settings would not open. Instead it started showing the message: Unfortunately, Settings has stopped Report Cancel The bug report would also not get reported when I press Report. So I tried to reboot the system. Although the phone shut down. But it didn't turn on anymore. I tried charging the phone for a couple hours, but in vain. I cannot even enter the recovery mode by pressing vol up + power + vol down keys. I tried browsing the net for possible solutions. The closest I came was this section *Did it gradually get buggy and then die?* on this link . How can I restore my phone's functionality?