Perfectly clear.
(1) You pay upfront in full.
(2) There is no cancelation charge 30 days out additional to the rate you paid and
(3) the prepayment is non-refundable
Yes, it looks ambiguous at first. But they're simply telling you that more than 30 days out there is no charge to cancel — some hotels charge cancelation fees — but you won't get your money back if you do.
The ambiguous bit is the implication that there is therefore an additional charge (not specified) if you cancel within 30 days of the stay.
That doesn't even reach the level of ridiculous. You prepay in full, and they charge you even more to cancel? Then why cancel? I don't see where they charge you an extra penalty on top of that for not showing up.