For coverage issues that are specific to one location, the culprit is usually the local tower especially if the issue was not always there. For this specific issue, we would need to speak with over the phone so we can gather some account level details and open up an engineering support ticket for you. Please contact us when you have a moment.
2 of 2 people found this helpful
tmo_chris gave you the best route in getting this resolved. However, while you are waiting I wanted to give some info on the possible reasons for the degraded service. 1. Is that there was a change that occurred that affected your line of sight to the tower. It could be a new building being built that is reducing service or something as simple as the wind knocking the antenna a couple degree off from where it was originally placed.
2. The other possibility is that its a device issue in which the phone is not connecting the best signal. I have had this happen often when in a fringe coverage area. The phone would drop to E when LTE was available.
Like mentioned though your best bet is to call T-mobile since they will be able to give you a more accurate answer rather than me guessing on the most likely reason with no info.