Verbal contracts, particularly in front of witnesses, can be upheld in some circumstances. When there are no witnesses, it is a matter of word against word.
Verbal contracts are binding as long as you can prove the contract itself exists. Often times if you have paperwork to document the verbal contract, it will hold up in court.
The verbal contracts are binding on both the parties involved but if one party refuses to abide by the same, the complainant has to give proof for the verbal contract.
I don't think they are, but you should consult a lawyer to find out more about it. The lawyer could tell you if you have a leg to stand on. The lawyer would know best.