My xiaomi mi3w suddenly quit connecting to 3g network even when it is available. I tried switching to wcdma mode from settings as well as by forced method. The sim card works fine with other phones. I tried factory reset, booting back to stock version, updating, etc. During the time glitch started I was using global developer ROM miui7 . I didn't do anything unusual. I can see my imei no: from settings.. what to do? It's serious..