Council Tax

Hello All

Could you please help with this one on the Council tax.
I use to receive Full housing benefit and council tax benefits

I recently received a letter last month saying they are suspending my housing & council tax benefits.
I called the benefits office and was only asked to provide utility bills and i was told all will be back to normal.
I suddenly received a letter on saturday making a final demand; for payment of outstanding Council tax benefits for the current financial year.
I have not had to pay this before now as i was receiving full council tax benefits.
Could you please advise, am i not entitled to a full council tax benefits as i was told previously that due to my illness and incapacity, i get council tax reduction and a remittance for the reduction from the benefits office, but i was been told today that i will need to make payment for this remittance. Please advised what has changed?
Many thanks