Is there a law against having garbage and multiple none operating vehicles on your property?

In the US it's called the "Nuisance Law". Check with your local court house and your local city hall so they can send the inspector to that property and issue them a citation for failure to comply.

Not all countries have an equivalent law, check with the local authority where you live.

Added: (in the US) this matter would be covered under local Zoning Laws which are stronger in some areas than in others. You had best check with your local municipal or county zoning office.