That's a good letter. I may have to borrow it if and when I get my letter.
Thanks honestly just be genuine, everything in there is absolutely true, there was no need to embellish, just state the facts and show them how it is in their best interest to fix the problem as well. So make your letter fit your situation.
Honestly after what I know now from being in the situation, I wouldn't wait to get termination letter if I were you, if you have already received a warning letter and you know that you havent been able to comply take proactive measures now to ensure you dont get the "letter".
Sprint Excessive Roaming Dept - 866-957-6899
Sprint Executive Customer Service - 703-433-4401
Good Luck!