Laptop vs Smartphone- multiple appointments issue

Hello, Nikola…
(Last Support request today!)

I was testing the Appointment form on both my laptop and my smartphone before going “live.”
I noticed that using my Laptop, (Dell Precision using Windows 7 and Firefox), I could make several appointments, using the same (or different) contact info, and the form would process beautifully- no problems.

When I tested using my Smartphone, (Samsung Galaxy S7), I could make one appointment only. While testing the form again, I could not get the form to accept taking another appointment request. Even after changing all the contact data, clearing the cache and cookies, and using different browsers, (Firefox and Chrome), it made no difference.

The only thing that worked was to increase the “Max number of appointments” setting in the Customize section of the plugin’s settings.

While that is OK, sort of, I wonder two things:
1) Why could I make multiple appointment requests (within a couple minutes of each other) using the SAME CONTACT INFO on my Laptop?

2) Why couldn’t I make any additional appointments when using my Smartphone, even when changing the contact info, clearing the cache, etc?
(How did your plugin know that I made a previous request if I used different info and cleared the browsers?)

Thanks!