T-Mobile at 2367 Foothill Boulevard, La Verne, California.

I went about 2 weeks ago because I was having trouble with my Samsung Galaxy S7. It kept restarting and draining the battery fast from 100% to 0 within 5 mins and I didnt know why. I told an employee at this store and he said they didnt do any diagonostic tests and I asked what would be the best thing to do and he suggested an upgrade as the best solution for my problem.
I told him I dont have that kind of money and he said he didnt know how else to help. Instead I did my own research and bought a battery on Amazon. Luckily I was able to solve my problem without the help of the employee who I thought was suppose to be knowledgable over the cell phones
Bottom line: They were of no help and I was a bit disappointed with this store.