The reason I said sign in to your account through Google Play, was so that you'd get the Samsung pack on your account. Getting it on a guest account isn't doing you any good. Bluestacks is just an emulator. Many software emulators need to identify themselves as something to other software or hardware. In this case, it looks like the Bluestacks software is telling this games servers that it's a Samsung device.
If you are on IOS, you could try to save your game through Facebook connect. Then create a Google account if you don't have one. Then try to sign in to Facebook connect from Bluestacks. This should load your game and allow you to save it. At the moment, I can't articulate this any better than I have. Hopefully, I've explained this well enough.