Hey sandrablue45! That's definitely not the behavior anyone wants in a brand new device. There are a few questions you can use as guideposts to determine whether this might be device specific or network related. Is this your first T-Mobile phone, and if not, did your last phone have any static on calls? Does this seem to be happening on all of your calls, or just with some contacts? Does it get better or worse in certain areas? Do you notice it improving or worsening when you're placing calls over Wi-Fi?
Just stopping by to see if you still need help with this. Were you able to get this resolved? Please let us know. Thanks!