sync up tracker goes offline

Looking for specific instructions on how to reset / initialize  … tried deleting and restarting n-times but none of ours have been activated since we switched our phone plan (> 3-weeks) to T-mobile 

I got 2 syncup trackers a month back.  Initially they would not Onboard at the store, but did about 12 hours later.  Worked for 2 days quite well, then not quit.  All efforts by hard working T-Mobile staff and tech support had not effect.  2 warranty exchange trackers arrived without the internal eSim cards setup, knowledgeable US support spotted that, setup, now working for 2 days  tracking well.  Now the tracker app is failing to connect to the back end servers on all phones, causing failed login and no updates from the apps already logged in.  The whole tracker system is appearing to be a weak effort, not a serious system, no fault-tolerance on the servers, perhaps weak backups,  coding errors on trackers (according to above experiences).  T-Mobile management, you are giving T-Mobile a bad reputation by what ever corner cutting / outsourcing strategy you are using.  Better to have no trackers than a half baked attempt.  It's also costing your staff and customers large amounts of wasted time.  In my case at least 50 hours at this point,  between 10 to 20 of your staff's time on just 2 trackers.  One has to wonder if the company has entered general failure mode,  am I also noticing a decline in store front customer service?  Services out of the Philippines is close to pointless.  What's going on guys.

Just purchased bundle of three trackers yesterday. Put one in a suitcase for a trip.  It was fully charged and worked fine from my home and then from the airport.  During flight, went offline.  So totally useless.  And cannot return because it will be out of the country for two weeks. :-(.  Feeling a bit scammed.  Will be costly to cancel at that time.