I was in the same impression at first but for your info, address started with "3" is valid for both blockchain; BTC & LTC. So, you can send BTC in an address started with 3 and you can send LTC in the same address as well.
This is exactly of most users that want to withdraw made them confused, because of the similarity of these two different addresses, even though you will get a mistake, still valid for blockchain that leads your coins to become lost. I guess the reason that I practice myself using Seagwit wallet address like its start of bc1 because there's no similarity on it.
But even though behind those mistakes by the OP, he's very lucky because it was refunded by the Rollbit, good to see there are online casinos like this and I think, it is a good start for them to build their reputation.
