How would I uninstall AT&T Call Protect application?

Two or three weeks prior, I was getting robocalls like clockwork. I introduced the application and it worked until I understood that it was obstructing each and every number that wasn't in my contacts list. Counting emergency clinics and schools... I had a go at unselecting the obscure numbers choice it actually keeps on hindering EVERYTHING. It's in any event, hindering numbers and new contacts that I've added. I took a stab at erasing the application it's actually obstructing numbers. How might I uninstall this thing??? Kindly assistance! I can't miss another significant call