Hello, I am Keith, one of the experts on Just Answer, and happy to help you with your question.
Occasionally these things do go wrong, unfortunately more often than you might expect. However, my advice is to check with the Tax Credit Office (TCO), you can find their address and contact detals on your award letter, and enquire what has gone wrong. You should have received notification from that Office of any change in payments. Remember you must notify the TCO of any alteration in your personal circumsances within a month of the change. There is also a possibility that the TCO has suspended or stopped your payments because your circumstaces have altered or they believe they have changed. Unfortunately the TCO have a nasty habit of jumping the gun in such matters or making assumptions which, in my experience, are invariably incorrect and always in the Revenue's favour.
If the money isn't in by Monday go into bat against the TCO! My file of my battle with the TCO many years back is two inches thick, but I won out in the end!
I do hope that I have shown you a way forward in this matter.