Well, you have the contract, we don't. Is being paid on time part of the contract?
Dates to be paid on (ie: 10th of the month) are specified.
I would ask a lawyer. I don't want to get you in trouble giving advice. I am not a lawyer. However, it does appear that the company has broken the contract. but a lawyer could advise you if it is wiser to push to get payment and finish the job or if you should exit now.
Equal Employment Opportunity Commission in Los Angeles can help you. Ask them for help.
Other people asked questions on various topics, and are still waiting for answer. Would be great if you can take a sec and answer them