Should we withhold maintenance?

We recently came to an agreement with my husband's ex wife about maintenance for their 15 year old son. She normally 'lets' us have him for 3 days every other weekend, and a few extra days if she has got something better planned, so I used the csa calculator to work out an appropriate amount based on us having him up to 104 nights per year and offered it to her as an informal arrangement, and she accepted it.

Recently, she sent my stepson here for his usual weekend, and we found out while he was here that she had actually LEFT THE COUNTRY for a holiday without telling us, and she was gone for 2 weeks. She had told my stepson she was going but nobody knew when she was coming back and she had told him not to say anything to us???? He hadn't even got his school bag or books here and had to go to school without them. As soon as she got home she ordered him to go back to hers, and he went.

She claims tax credits and child benefit for him, and gets maintenance from us. We also have other children and get tax credits and child benefit for them, although not for my stepson. My husband has lost a lot of work recently and we are struggling a lot, whereas my husbands ex wife has taken 2 foreign holidays in the last 5 months and countless weekends away,(all without my stepson)She goes to endless concerts, and this week has been bragging about getting a new settee!

My question is, are we within our rights to hold back a weeks maintenance from her for the time that she left him in our care and went on holiday without asking us?

We simply cannot afford to pay her 'and' feed him and pay for his school lunches, and all the activities she has signed him up for. I always pay the maintenance at the end of the month (just in case she runs off and leaves him for good!)

Thanks

Don't withhold maintenance. If H is being paid less renegotiate CM on that basis and keep a record of contact for a year, then renegotiate based on the number of overnights. When you calculated CM did you deduct an allowance from H's income first for the other children in your household?

littlemiss.
As fiona says you shouldnt withhold maint.
Also do you deduct money for your own kids? as fiona says, I beleive its 15, 20, 25% for number os children off the amont you pay her.
The CM is an amount of money over a year that you pay towards the upkeep of the child, so the system is not designed for interim payments to be taken off.
Having said that, i know exactly how you must feel, but dont take it personally about her life, let her do as she wants, you and your husband are. If his earnings go up and down, I would pay an amount maybe each month based on net, or do an average.
Might be worth mentioning to her that you need to know if she leaves the country for the sake of the child. Say that you dont care where she is going or who with just need to know times, ask her is that fair?
(might not get a good answer to that!)
Youmentiont he things she has signed him up for, that is also part of what the CM pays for, you dont have to pay extra ulnless maybe yo pay for an activity all the time.

Good Idea guys. I did the original calculation using the csa online calculator.

Although now, taking into consideration that period she left him, and along with the set times that we know we will be having him for the rest of the year, it has bumped it up into the next category for the amount of overnight stays he has with us each year, so I have recalculated it and the weekly amount has come down. This means that she is going to lose a lot more over the year than just the one weeks maintenance! I can't wait to write and tell her. Maybe she'll think twice in future.

Thank you all

Thanks bobbin, however trust me when I say that there is NO reasoning with her. We believe she suffers from narcissistic personality disorder so she would not see anything wrong at all with leaving him behind without saying. The would think its her right as his mother. In fact she has even told my husband that he should be grateful to her because she 'let' him have their son while she went on holiday. As though she went away just for him!!!