signature on contract

I'm a self employed janitor. Ninety nine percent of the time people don't sign my contract but I begin work and get paid. This time the people won't pay saying that they didn't sign the contract. Can they get away with that although I performed the janitorial service for them for a month. Isn't them permitting me on the property to clean some kind of evidence of acceptance of my contract even though they didn't sign the paper?

You should be still able to get paid. They received a benefit for the work that you did regardless of the signature. Write a demand letter and threatend court action. If nothing is done and depending on how much it is take them to small claims court.

Thanks legaleagle. Appreciate it.