I am trying to create a booking system for users to choose the day and the time they would like system updates. I have created a list in sharepoint 2013 by pre populating all the dates and times that are available for users to choose themselves. I display a web part in a page and show a filtered view of available slots which are dynamically updated using a filter on the updated columns, as people select a slot, those slots are removed from the users view. I also use this list and put it in an overlay calendar, also embedded on the page and showing the time slots that have been chosen by users. I have tried unsuccessfully using InfoPath to create a form to embed in a web page to allow them to select by unique slot number in a dropdown box and then be able to update the extra details fields in the list they need to fill in with their names and contact details.
How do I set up the form for them to only be able to edit the data that is already in the list and not add new data and secondly how do I hide the slots in the InfoPath drop down box they have to select from, that have previously been taken and have their data completed? I've included an example below of the list. I have tried using the date column in a separate lookup list in a separate look up table, but then I could not use those dates in an overlay in a calendar. Any help would be much appreciated, I am not a programmer, so if there is a solution using InfoPath rules or designer rules I would appreciate it!
