What do you mean by the address is the same? If they were then your account would have been credited regardless of the network (BSC or Polygon). This is all entirely because of your mistake or inability to pay attention when making a deposit so you can't fault them or even create such a scam accusation.
Trying to retrieve those funds isn't as easy as you think. This is a service handling thousands of accounts and transactions.
Sportsbet.io uses different addresses for each type of network, it doesn't have to, but it does
You did stake though "I leave the Polygon and BCS address (which is the same for both cases) and the TxID", that's why logfiles said that. So what is it then?
I had a similar situation before, sending on the wrong network, on 2 different sites, and both times I got the same reply it's my fault and they can't or won't recover it.
Even more annoying, at betfury I sent some ETH but it was under the deposit limit which is like 15$, now the money is sitting in the wallet (which is my betfury eth wallet address) and will be stuck forever. I don't know how this can be since normally funds should go directly onto your casino account. Setting a limit and not moving it to the player's account is a real scam for me. At least it was only like 13$, a cheap lesson to just keep hating this terrible casino site.
In casinos like stake they give you the same address for any Ethereum-based token network when you deposit, this does not happen in sportsbet.io, they have a different address for each network.
This means that in another betting house the balance would probably have been credited since the network would be indifferent, I am not saying that sportsbet.io is guilty, just that after seeing that the token is there at their address with the BCS network, they can access the funds, perhaps they do not know it and they will be there without being used.