Hi!, Looking for help with a bust pizza and sandwich takeout store.

Looking for some help?
We are getting very busy and starting to run into problems with timing for customer on getting orders out.
we have a POS( Shift 4 ) and use and online platform that we need to enter orders from a tablet. just curious what’s the best plan of action to stop the bottlenecking? do we give out time slots? customers do not seem to listen to the times they are give? 

Thanks for your help!