Only suggestion is that you call the police, and do it now. If they truly are using Meth, then the home may need to be fully rehabbed, as per state and local environmental health standards. You can try to call the owners, but if it's a bank, good luck.
You will probably need some sort of proof before the police will come out, but I would call them anyway, if it's affecting your home value (and it will if they're using). Good luck with that.