So far we have never had a problem with them with renewals, but your post is making me nervous for the future lol.
I do recall a while back seeing their financials because they are a public company in Canada I believe (don't quote me on this, its been a long day and a long time since I saw the article), but they were definitely not profitable.

I assume you asked them about it, what was their reasoning for not paying you on the renewal?