You are entitled to your past spousal support that was ordered by the court. Your ex can seek a reduction in his spousal support due to change in circumstances but he would have to take action by filing an Order to Show Cause Re Modification. The spousal support award that was previously ordered is still effective and the burden is upon him to seek the modification. If you wanted to collect on the past support that he has not paid you can either seek a contempt order or file an Order to Show Cause to determine the arrears. I would probably do the latter because a defense to a contempt for failure to pay support is his inability to pay due to his lay-off. I would venture to say that if you seek to have the court determine the arrears he will file to have the court reduce his support. Once the court determines the arrears you can then enforce collection by any lawful means including garnishment.