Sorry if this has an obvious fix but I'm not sure where to start.
I recently started at a very understaffed coffee shop and soon found out that everyone was staying at least half an hour after our shift ended (according to the rota) in order to be able to close properly, every single day. I was OK with it until I found out we're not being paid for that time. I asked the manager if they could adjust my “actual hours worked” on the app the company uses to record hours but they told me that they made it very clear from the start that any work done after the end of the scheduled shift is entirely voluntary (they didn't – I just stayed because I thought I would still be paid for that time).
Here's the problem: I would be perfectly OK with walking out on the dot but due to how few staff we have, most days that would leave only two people to close the (pretty sizeable) store on their own, and I don't want my coworkers to resent me because I'm planning to stay in this job for the rest of the summer. And it means they would be walking out even later without my help. I asked my coworkers if they would consider sticking to the rota perfectly until management noticed that the store was a mess and were forced to give us more (paid) time to close up, but they said that would only mean the opener has to come in earlier to get everything done, and that's always only one person so it's an even worse alternative. I asked why it was so important to them that the store was kept running smoothly and they said we get small bonuses based on customer ratings every month and they don't want to lose that.
I'm at a loss. The manager keeps pretending this “after hours” work is voluntary and my coworkers have already complained plenty to the area manager (though I don't have their contact because I'm new to the company) and nothing has been done. The problem is that this store suddenly lost a lot of staff within a couple of months before I came, but with them it was possible to close within the given time and management refuses to see that it might be different now.
I just don't know who to complain to next. I don't know if we have a HR I can get in contact with because it's a really large company and I was never given a procedure to follow in this scenario.
This is in the UK by the way. Suggestions appreciated, but something feasible within the time frame of now until September. Or maybe that's too short a time to achieve anything and I should just suffer through it?