housing benefit payments

hi i was just wondering if someone could help me,

i recieve my housing benefit every 2 weeks on a friday, they say its due on the monday but has always been in my account on the friday,

my last payment was on 22nd march (due 25th)

today i recieved another payment, even though my payment technically isnt due untill monday 7th!!

i just phoned birmingham city council and the woman was useless, she said yeah it might be nexts weeks payment early but then it could be an extra payment, i asked her to check my next payment, she said she cant!!

also she said the payment i got today was from 25th march to 7th april, does that mean im due another payment on the 7th, which is monday!
arggghh i dont know.