I was in charge at my retail workplace for the day. The managers weren't available and I was placed in charge. I'm not too familiar with work rights but I understand a few. My coworker asked me if they could immediately take their lunch break. As it wasn't their time to take their lunch, my response was that they could rest a bit. And if they absolutely do not feel well after resting, then they could leave work. They complied and went into the office to rest. A few moments after I noticed they left to go home. I later found out that they texted my assistant manager if they could go home due to them feeling ill. My assistant manager then showed me the text stating that I did not let them leave and that they know their rights as this is unacceptable.
I am aware that if employees are sick, it is inevitable to let them leave even if staff is short. However, I did not out right told them that they must stay and I had given them the option to leave after taking a rest. Am I still at wrong?