I fail to see anything in your experience that makes them Grade B. I mean they didn't take money then turn into monkeys or give you bad service. They just rejected your order which even puts them in grade A because they didn't waste your time.
I suggested talking because it may be just that you ordered through a proxy (which many hosting companies consider as fraud) or any small detail that made them reject your purchase.
You wanted to be their customer and pay them and they refused because your order was a potential risk to their business. This is what they think so it's up to them.
You are the one who needs not to have hard feelings. Just pass on and deal with another host.
Tips for getting through ordering process for any host/service
1- Don't use a proxy. Unless you are doing anything dodgy then there is no reason to hide.
2- Use email account from one of your own domains. Many of them will not be ok with free email providers.
3- Put correct details about country / state. It doesn't harm you if you are a legit customer as they have your IP anyway
4- Read the service description and know what for you and what's for them. Read the terms to be clear from any problems in the future.
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