Problems after upgrade

Hello!
I've been using tyour plugin for a long time and there were no problems. Now when I try to pick another date, it doesn't change. Or if I can, when I click on the selected hour, it doesn't work. I can't also use See Details and Edit link as it doesn't work.
Another thing, I was getting an email with confirmation (A new appointment has been made on Escape Factory Pozna?. Below please find a copy of what has been sent to your client and now it is not working as well.
Another thing: I was able to translate some fields earlier (like the legend for the 3 colours in the calendar). Now it's impossible.

I will be very greatfull if you will help.