"These days they have streamlined online applications for writing to them, but I suggest that you only send them paper letters. This is a really weird thing for a technologist to suggest, but when you send paper letters, you can establish and own a “paper trail.” When you type words into their godawful web applications and hit submit, you will likely fail to retain a copy of those words and fail to retain records about what they told you (exactly) and when. This will complicate your resolution with them. Communicate with them only over postal mail. Keep a log of every mail you send (including what you said) and when it was sent; keep a copy of every letter they send to you and when it was sent. You don’t need physical copies; digital is fine. I like organizing all of mine on a per-incident basis in Dropbox."
YOU SHOULD ALWAYS SEND LETTERS WITH 'USPS RETURN RECEIPT REQUESTED.' (It's the green card you get at the post office and once the recipient receives your letter, you will get a green card in the mail serving as proof of delivery and acceptance.) This is the lowest costing form of legal proof for a paper trail. Well worth it. I use it all the time and I learned this from my dad who has spent his life practicing law.
YOU SHOULD ALWAYS SEND LETTERS WITH 'USPS RETURN RECEIPT REQUESTED.' (It's the green card you get at the post office and once the recipient receives your letter, you will get a green card in the mail serving as proof of delivery and acceptance.) This is the lowest costing form of legal proof for a paper trail. Well worth it. I use it all the time and I learned this from my dad who has spent his life practicing law.