My b/f moved out & has left me to pay $500 for landscape work. Only HE verbally committed to this. Who pays?

There is no written contract, and the landscaper has called to say he will take me to court for the money. Is it ethically or morally possible to make me pay for this work, just because the residence is solely mine. Mind you, I had NOOOO input on this verbal contract, only the ex and this miser of a landscaper did. Please help and inform me of my rights!