CSA is causing me debt problems

in 2003 the csa got involved with my voulantry payments to my ex and six months later sent a doe to my employer but they failed to collect, i carried on paying voulantry payments my self wile trying to get the csa to sort the problem.

It took them 3 and a half years! to finaly work out what i should pay and in 2006 they started collecting money , great i thought all over, my oldest daughter left full time education in april 09 and my son started work 6 months later leaving 1 child to pay for. I contacted the csa in august 09 to adjust payments but got know where, so in january 2010 i wrote to my mp for help this seem to work and got my payments reduced , then out of the blue a phone call saying i owd arears from 2003 until now.

I explaind to them i payed voulantry payments becouse they could not sort it out and they already had all the paperwork to prove it, but hey guess what they have lost every thing! and now i’m struggling to find it all again, why should have to be left in debt becouse they took over 3 years to sort my case then lost it all and want me to pay again this is no more than leagalised extortion.

Incedently i had a good relationship with my ex until the csa got involved and destroyed it! any comments or advice is very welcome because i do not know what to do apart from jump of a bridge!