i had a similar thing recently, laid off for minor misconduct, had a verbal warning earlier this year then pulled in the office a couple of weeks back & told my contract (that i never signed) had been terminated with immediate effect, i got 1 months pay in lieu & told to collect my personal things & leave the premises straight away.
i knew there was something wrong as a couple of weeks before the missis got taken into hospital & i had to look after the boys so couldn't go in for 2 days, i let them know both days but when i went back i got questioned about how i was letting the company know i was having time off, i told them the reason why i was off & it wasn't planned, i believe i was getting backstabbed by someone else though!