No duplicate row

Hello to all

I have made a list of prospects and I want to invite some prospects to access my application

I have a table A (Annuaire) and a table B (acces)
Table A and table B contain people

I display the list of people in table A
I select a person to display his record with details (name, email, tel)
On this record I click on a button that should copy the line from table A (name, email, tel) to table B and send an email and SMS to this person to notify him.

It works but I have two problems
1/ In the same scenario I can’t send an email and then an sms - it sends the first one but it doesn’t follow on the second one (it seems that the scenario is stopped with this type of action) - so I made two buttons SMS and EMAIL but it’s not the way I wanted it to work

2/ If my prospect is already in table B (same email address) I don’t execute anything to avoid notifying the person several times and especially to avoid creating a duplicate in table B

Thank you for helping me to get around these two problems.
Ludo
Capture2
Capture1

for the duplicate problem finally I found easily

in table A I added a relationship column (email with table B)

if this value is not empty (so it means that this email already exists in table B) I simply hide the button !