liability order

my husband received a letter from the csa at the end of october saying he owed £8,000 for 2 children from a previous relationship, they gave him 7 days to pay or they were going to court.

Well we couldnt pay the outstanding amount off but we did offer to pay £100 per month, (my husband lost his job in nov last year and we have a dmp put in place as we have found ourselves in so much debt and unable to pay our bills), we cant afford to pay anymore than the £100 per month, anyway, the liability order was granted even though we have been paying by direct debit and now they are saying we have to pay £350 per month or they will send the bailiffs in.

I’m worried sick what will happen, we also have 3 children under 4, including a baby, we have gone to the cab but they havent really helped us we just dont know what to do next.