p.s : there were also lots of negative feedbacks if you will only do a backread . why didnt you scanned this thread before trying something that your not familliar with ?
It's useless to ask that question since he has sent his sumo coin on there.
When i search on CMC,
https://coinmarketcap.com/currencies/sumokoin/#markets thta exchanhe even didn't listed as one of sumo coin exchange, that's why the only one way to withdraw hid money is buying more sumo coin and then withdraw it.
I couldn't remember exactly, but they were on CMC or coingecko. But I don't have any idea why they were removed completely. It looks like your solution is the only choice.