Trying to contact AT&T after being promised a resolution several times and let down

I have been a customer with AT&T for Almost 15 years now and would SIMPLY like an email contact address for Customer Service/Satisfaction where I am able to send an email detailing an issue, receive a confirmation of receipt & hopefully, in a reasonable amount of time, a response.

I have been UNABLE to accomplish this SIMPLE TASK for weeks now - I have used the “live chat”, I have called numerous times only to be transferred to another department who claims they can not help me and i should be transferred to another department, get put on hold and eventually hung up on without any call back. I have spoken with several agents who have assured me that my issue would be resolved. I was even given a case number with a date of promised resolve only to later find out that it was not resolved, and only found it out because I had to investigate and look into it again myself. 

Needless to say I am both frustrated and angered by the manner in which AT&T has conducted itself as a company - someone must be accountable so if there is anyone who reads this and is able to assist me in any way please. 

I will be most appreciative & grateful,