10000:1 says the "R" (2nd letter of fare basis) is for "roundtrip", implying that as a 1 way ticket, there is no residual fare left over. It requires roundtrip travel, or at the least, an open jaw. Most likely you can exchange the return leg for a much cheaper return, and would be entitled to the fare difference.

That fare doesn't currently exist, so to find the rules, I would need to know both ticketing date, and outbound travel date.