Can I be ticketed for public indecency, suspicious activity, and attempted robbery because I pulled into a parking lot to make a phone call?

Are you being charged criminally? Can you give me a more detailed description of the circumstances? I'm not even aware of a civil fine related to those allegations (especially attempted robbery).  Have you received a summons in the mail? 

Many people nowadays are not allowed legally to make phone calls with their cell phones while driving. To be safe and not be ticketed for such activity, many do pull over into store parking lots to make a phone call, especially if they are looking for directions or late to an appointment or meeting someone. Public indecency, suspicious activity and attempted robbery are all mutually exclusive criminal violations but I cannot see how those three in particular could occur in one event unless you were not clothed in a vital area, you appeared either high or drunk and of course, if you had any weapons on you or were in a location or position that it could be reasonable to assume you were about to commit robbery. You can be ticketed and or arrested but for attempted robbery I would assume you would be arrested. Otherwise, it may not have been robbery but possibly some minor form of petty theft. If this actually occurred and especially if this is your first series of allegations issued against you, you may to seriously consider consulting with a criminal defense attorney about your options and the evidence against you.