Dear worker, please remember…
Just because a “friendly” detective is nice to you, it doesn't mean he is your friend: his job is not to protect you, but to find the guilty party. Therefore, you should always have legal representation.
Similarly, a company is not your friend just because they sweet talk you or when they talk about valuing loyalty or (specially) when they “warn” you about how bad unions are for you, they just want to extract as much money as possible from your work while paying you as little as possible. You are not their friend; you are a burden that costs them money. If they no longer need you, they will not hesitate to let you go.
As someone from across the Atlantic, I wonder why you haven't unionized and fought to improve your working conditions. I understand that unions are not perfect, even here we can see that, but I can't help but feel sorry for you when I see how you tolerate the way companies treat you with BS excuses.