So let me get this straight:
You were 45 days past the signing date and weren't paid and thought it was ok to come here and say "Beware of these guys for taking a while" (You're right to do so)
You then get worked up when someone suggests to send a collection letter on the 35th day to help expedite payment if not received. You also seem to view this as a problem.
I'm having a hard time understanding why the second part is so out of the ordinary to do, but you had no problem doing the first.
Listen, we get it. If you're new and havent been taking a ton of signings, the money coming promptly is very important. With that being said, relax and keep working on getting more signings and partnering with more companies. When you get busier, you wont even notice that someone took a couple extra days(two weeks in your case) to pay you.. Now, you'll still track things and I'd say once you get to two months, then you should start making a big stink about not getting paid.