WOW guys, after struggling for months, I've finally found a solution for this problem.
Details on my situation:
I bought a T-mobile iphone 5s in Mexico that i unlocked successfully with R-sim.
My iphone is on ios8.2.
After 2 weeks of usage, i noticed my wife wouldn't respond to my texts or calls. I began to wonder, then i realized that i could send texts and realize calls with no problem but not receive them.
I struggles with Do Not Disturb, i restored my phone, i reset network settings, and waited patiently for other alternatives while researching EVERYWHERE!!!
I was starting to blame the heat, the rsim, the Telcel signal down here, and endless culprits.
I read on the most unlikely of places a tip that caught my eye.
I read something about a conflict caused by LTE, 3g, 2g and home wifi signals, which caught my eyes because i knew days before i noticed my problem i fiddled with my settings.
AMAZINGLY, when i switched Voice & Data under my cellular setting to 2G, IT WORKED!!! i receive calls, make calls, receive and send text, no internet due to the unlock but its ok.
I really hope this helps guys, i know i had special circumstances but hey, any help is useful.
I hope my post isn't removed because of my methods, but give it a try guys and let me know if it results.