I work for Nochex and I've only just come to this thread via your message. Going back to disgruntled's original message I think the problem he came up against was because he had a Seller account. This is meant for people selling small numbers of low value items on ebay and such. Unfortunately, we had cases of people using these accounts to trade that is not consistent with acceptable use so we have had to take a closer look at all these accounts. It sounds as if disgruntled got caught up in these by trying to trade at a higher value than is allowed and was asked to upgrade to a more suitable account.
To go back to your point what has this got to do with all WHMCS users, well not a lot if you aren't a Nochex user! However, I'd go back to m8internet's point which is to do your research so far as the services you use. disgruntled is proposing to use Google Checkout, but it might worth doing a little more research there as they may be much more perfunctory than we have been in closing accounts if they don't like what they see.
Happy to answer any questions about Nochex and payment services in general if I can.