How can I contact T-Mobile Corporate Office?

Some how it is hard to say that is there a worse cell phone provider than Straight Talk. T-Mobile has made the bottom of the list of all cell service providers. Reps make many excuses and try to make the company rules work for them and thrown the customer under the bus. Corporate stores vs authorized dealers are so different that they do not align with corporate. The sales rep at Walmart was a complete liar and tells you what she wants to gain a sale. I have been dealing with these none working phones for 4 months. Billing issues for 3 months of over charges, cause the Walmart rep did not set it up correctly, Then phone reps promising that it has been fixed. Three months later still automatic drafts with over charges. So I am out of town and T-Mobile overcharged me and I was not able to get a hotel room for the night ( I was out on business), so my wife and I had to sleep at the grocery store parking lot. I address the concern with T-Mobile and they did not care. My phones from day one had not worked properly since day one. I called and had many promises to repair, call backs and neither had been done. The last rep/supervisor over looked that I said day one and said that I had 30 days to take the phones back but placed it on the authorized dealer when I had been calling in. Everything there after then revolved against the 30 day return policy. Therefore no resolution, tried escalating and he says he is as high as I can escalate other than writing a letter my mail. So how does it take 4 months with no resolution from a company like T-Mobile. We made the move to get away from Straight Talk bad customer service and T-Mobile ended up being the worst! So my recommendation is do not buy from an authorized dealer, they have the bottom end of the products and they do not align to T-Mobile. If there is no stock do not get into the contract as it will mess everything up. Read everything cause T-Mobile does not  care about you once they think they have you locked in. I have asked for escalation or call from corporate and was told nobody will call us back. So it really looks like I am searching another carrier.