Most that deal with gear make their plans weeks in advance, they won't change their mind 3 hours after the purchase, this is the thing that triggered a lot of red flags in the OP story, even without the whole ledger thing.
Yeah I agree that OP situation is indeed weird + his unacceptable behavior, but as someone who only buys from places with good customer service, this no refund thing would be a deal breaker for me as not once I sent back quite expensive pieces of electronics (usually its Amazon).
I never bought any mining equipment from one of those specialized sites so I didn't know that's how they all operate, but back in the early 2014 I ordered 2 high end GPUs from a computer store (wanted to mine some coins lol) and after 2 days due some unexpected life circumstances I had to cancel the order.
And, look at that:
What if he used somebody else account and coins to pay?
Well, there should be some way to check whether OP is the real owner of the account, and didn't he say that he is in control of the email that is used to create the account? Anyway, I am not saying that he should be automatically refunded to a new address without a proper verification but just just that whole "no refund" policy would be a deal breaker for me, and he should have read their TOS before doing any business with them.