Hello, this is my first post in antiwork so sorry if there's anything that's not good with it.
I am UK based and years ago I started working for this international company. The job is usually one shift per week and each shift can last around 3 to 8 hours, usually on Fridays and weekends. The manager requires us to give availability of days for the month at the beginning of the month. At 2-3 days before each shift we would then be told the hours of the shift. We then can either agree to them or ask the shift to be modified if perhaps it ends too late.
I am unsure if I am a part time worker or a 0 hour. I believe to be the former as I remember being told that it was a part time job by a colleague that was doing my training but don't have anything written like a contract to confirm it and anytime I ask about a possible contract to check about some job policies it gets dismissed by my manager.
The issue is that at times I attended shifts where we meet our group target earlier than when the shift was advertised and our shifts would be cut shorter on the spot (it's a job on multiple locations with multiple people contributing to the same goal). He would message the whole group that we have met the target for the day and we can go home. On multiple of such occasions I've contacted my manager about payment because it was unclear if we were getting paid for the full shift we had agreed upon or only until the target was met. I personally think it's unfair to get paid less because we worked well. Each time out shift ends earlier I have to ask him otherwise he won't mention anything and I'm told a different answer and that he's not able to give us a way to know if we are paid for the full shift or not without having to ask him each time. Sorry for the wall of text.