A.L.
I handle the wage garnishments at my job and can give you a little insight. First off you need to get a copy of what your employer recieved. By law they need to provide that to you. They may have put the garnishment on the wages but have not yet turned them over to the creditor as we usually get the intent to assign wages and must garnish until we get the official court order and then just hold the money until the court order is granted.
At any one time you cannot have more than 15% of your wages garnished no matter how many wage garnishments are pending. It is a first come first serve type of thing. So the first one filed gets the 15% until that debt is satisfied and then the next wage garnishment will be applied at 15% and so on.
If you want more info you can send me a message. Hope that helps. Sometimes you can contact them and explain your situation and set up a payment plan to forgo the garnishment. Something is better than nothing.