Ive been suspended pending an investigation. Please help.?

work in a care home and i support adults with learing disabilites and mental health. Yesterday I had a phone call form my manager asking me to see the management before i start shift, so i went in and went to the office, the managers said to me that ive been suspended pending an investigation I asked them what for and they said apparently I had spoken ually in front of a patient or to them and they someone was there when i suppose to of said it and the client had made an allegation against me, and that i was ment to of said it on the 10th of april which was six week ago and i get suspended. Im so frighened that they are going sack me for something i didnt say and try and get false witnesses to testify against me. im really scared cos they are trying to get rid of staff at the moment. Please can i have some advice on what grounds they have prove that i said any of this????