Applications used to be able to be done over the phone and payments received within a week. Stricter security checks and delaying tactics are the cause of long waits in receiving Tax Credits.
You are entitled to compensation if you have suffered financial hardship and or expense at HM Tax Credit's office failure to deal with applications in a satisfactory way. This used to be within three weeks of returning your application but this timescale now seems to have been removed from information supplied with claim forms.
I have been given over four different addresses by the Tax Credit helpline to post complaints to and very seldom get a written reply.
Just don't let the b*ggers grind you down and once you have submitted all the info they require and waited three weeks contact your MP to chase up your application whenever you are experiencing delays in receiving what you are entitled to