Mugg and Bean horrid service, ****ty app, never again

I downloaded the app and got a free cappuccino for signing up and then a free slice of cake for my birthday. When going to the mugg and bean at table bay mall inwhich it first too 10mins before anyone could figure out the bar code, only for it to be invalid. At this point for some reason our order had been made already. The manageress came to assist and then told me it's not working and demanded I pay for my coffee order which were supposed to be free. Not only am I furious about the app setting me back but the audacity of the manager telling me to pay in the way she did. As there were people around I didn't want to make a scene but at this point I should have. The service was horrible and that manager needs to learn some skills training. Mugg and bean is expensive and that was why I thought I'd enjoy a birthday coffee. The coffee ended up being cold too. Didn't even bother with the cake. Will never go to mugg and bean again. Don't bother using the app. It's a waste of time.