For the last month now, my mobile connection has been unreliable, frequently I make calls, and it connects with no sound if I dial out. If someone calls me, no problem. Also, the "4G" connection is equally sporadic, sometimes claiming I have coverage, and then still not connecting to the internet. The only reliable way for me to make calls right now, is through Whatsapp on a home wireless network. There is definitely something wrong. Help?