SnapSwap is an XRP Ledger gateway for EUR, USD and BTC. The BTC section was later taken over by the Btc2Ripple gateway.
Unfortunately, the SnapSwap/btc2ripple gateway seems to be no longer operational. Our users report that SnapSwap (or its successor) don't respond to queries and don't honor their own IOUs.
You can still trade SnapSwap's IOUs for others, but their value has been very low on the market (for the reasons stated above).
Please note that GateHub is, and never was, in no way affiliated with SnapSwap, or any BTC gateway on XRP Ledger other than GateHub Fifth. XRP Ledger users use gateways other than GateHub completely at their own discretion.
Just as GateHub does not recommend using SnapSwap or list it in our wallet, we also can't prevent XRP Ledger users from using defunct gateways as users' XRP Ledger wallets are under the user's sole control.
The only way for an XRP Ledger user to obtain SnapSwap balances has always been that the user explicitly trusts the SnapSwap gateway. This was usually done in the old RippleTrade interface (unrelated to GateHub) as GateHub doesn't list the SnapSwap gateway.
To prevent issues with defunct gateways, we suggest our users remove all trust lines issued to gateways that the user doesn't in fact trust, and also disable rippling on remaining trust lines.
More information on the SnapSwap issue and possibly some suggestions from other XRP Ledger users is available from online XRP Ledger forums like https://www.xrpchat.com/.