My T-mobile Apple Watch Series 4 LTE is unable to receive calls when the paired iphone is turned off. I'm able to make calls, send and receive texts from the watch but when receiving calls, it goes straight to voicemail. T-mobile thought it was because the watch had one bar signal and to try a place with a minimum of two and over. I tried different places with two to four bars but still having the same problem. It's also the same when connected to wifi and the paired phone is off. Anyone have any suggestions, thanks in advance.