I had a bad experience because I was leaving and I wanted to stay just part time, so I told them with one month in advance instead of two weeks ( which I could have done it, because I was on the probation period ) which would have been safer for me, but I wanted to be fair and give them time to think about it.
Next day they sent me the end of contract letter saying my contract will end in two weeks.
They not only left me with no income for 3 weeks, but I was expecting at least holidays pays and extra hours, and instead, they are asking me to pay them back because of some miscalculations from other payments...