Lots of manufacturers/distributors and others close accounts for lack of activity but who does it may depend on the industry. I had an account with a marine parts/supplies distributor and they closed it because I didn't meet their $5000 minimum for annual sales.

WRT someone telling you they don't want your business, I would look at the correspondence and see if the messages from you may have caused it- most CS people are thick-skinned enough that they won't take a few comments personally because A) they don't own the company and B) why alienate customers?

I know/worked with people who treated CS reps as if they were trash and the CS rep isn't going to do any favors in that case. One time, I called Sony and at the end, she commented that the others from our company had yelled at her when they couldn't get her to cover equipment that was out of warranty. That doesn't work but they usually won't act that way just because they're having a bad day.