Report Lousy customer service

How do I report? Absolutely horrible customer service? I went into the T-Mobile store on 48th and Owen and Lincoln in November to buy my son a phone. I was told by the representatives there that if I added a line I would get another line free. we talked through this I did not need the line at that point in time but he assured me if I did it, I would have a free line for life and since I have another younger child in a couple years, I would have a free line. When I received my first bill, of course it was $25 more than it was supposed to be. I contacted T-Mobile customer service and they said I was an eligible. I went back to the store and they said oh we thought you were eligible but you aren’t there’s nothing we can do. The store has said there’s nothing they can do  The customer service online has said there’s nothing they can do. Although several people have tried to help me and we’re giving me credits and told me it was taken care of and then those credits are not approved. I was with Sprint for 22 years and never had a complaint. I’ve been with T-Mobile two years and those two years I’ve twice tried to add a service  And the plan that was sold to me in the store was not honored by T-Mobile online. Each time they said I was in eligible for the promotion that was offered to me in the store. I am beyond frustrated as I can no longer believe anything that a T-Mobile representative tells me. That goes even further, when twice T-Mobile representatives have told me of the credit they will be applying to my line or to my bill  And then later I’m told we’re sorry that wasn’t approved. I have those saved in my history exchanges with T-Mobile. How do I get the store manager to contact me to see if there’s some amends that can be made? I’m not unreasonable 22 years with sprint never a complaint two years with T-Mobile and I am looking to switch  Providers and also to spread the word that whatever is told to you in a T-Mobile store is non-binding by T-Mobile. It is absolutely amazing and so frustrating. I hope somebody who can do something about this reads this and will contact me. I am a family of seven that will have phones for years to come but apparently T-Mobile doesn’t value me enough enough to honor what was sold to me in the store