Fails to complete a swim workout and setting up the LTE function is impossible

Frustration is up, four weeks into this 945 LTE and it appears impossible to set up the LTE and it has yet to complete a swim workout built in the gamin app. I've never had this problem in any of my previous Gamins. It'll do the first few intervals, then skip a few, randomly start another interval which it won't complete only to randomly end the workout when it wants. Customer service honestly has been horrible.