I think
@Odinsraven makes an excellent point.
It all depends on the contract. If the contract says the deposit is lost, then we should really not be looking to "name and shame" the outfitter involved. Yes, many do roll over deposits, even if written contracts would allow them to keep it. But if the shoe was on the other foot, and the hunter was insisting that a term in the contract be adhered to, we would all support the hunter 100%.
I like to think I'm a man of my word, and if I sign a contract, I won't be critical of the other side for asking that I live up to it.
I just booked a hunt for the end of September. The (standard) contract said at this point I would lose my deposit if I cancelled (this is in Zimbabwe where quota has to be allocated). I asked if I could roll it over to next year if something came up, and got written confirmation that I could.
Hopefully your contract is either silent or gives you some flexibility. If not, then the lesson is (1) make sure you know what you sign, and if you see terms you think might be a bit tough, try to negotiate them. If the outfitter won't budge, then you can accept or look for another outfitter. Hunting is a very competitive business in Southern Africa. Second lesson is trip insurance.
Lastly, I hope the procedure is successful. Best of luck.