Hello, I changed from $55/month 1GB + 1GB Bonus plan to $55/month 1GB + 2GB Bonus Shock-Free Data with unlimited minutes and unlimited messaging during the Christmas promotion. In the past, it was under LTE on my iPhone 6s+ most of the time. Only occasionally I got 3G in a few places. Now, I have noticed that for the past few weeks, it is in 3G only. Know what is going on?