Ex Filed With Child Services

I have been divorced for six months. Recently I fell behind in child support by 1/2 a month. My ex is not a rational person so she filed to have money taken from my check with Social Services. I received a notice from SS that they were not planning to take money from my account at this time, but it appears I have the opportunity to dispute the arrears or amount of the CS payment.

I was planning to make a payment on 3/18/11 to bring me current. According to the paperwork from SS, I have 10 days to respond to their letter. Although I do not dispute the back payment or the amount of monthly CS, I am concerned about having it taken out of my check each month through my employer. What can I do to prevent this situation from occuring if I am current on my CS?