I haven't ever used the website you are talking about.
I just made a search and seems that the service you are referring to is an exchange.

Note when you put your crytocurrencies on exchange, your coins are fully control by the exchange and there is no way to get a private key or a seed phrase.

I don't have much information about BSC network, but if there's a way to recover your fund, that can be done only by Coinlist.
So, the only thing you can do now is to contact their support.