Problem with OLED Display Voltages (String Command) using transmitter and Receiver

[red_car]

Couple of points:

This code

@mubashirazmat

   int i = 0;
  if (i >= 0) i++;{
  Serial.println ("$ABC, 12.10V,\n"); 
//  Serial.print(Voltage);
}
i = 0;

... is equivalent to

  Serial.println ("$ABC, 12.10V,\n"); 

This is not a good idea...

int i = 0;

  for (byte i = 0; i <= 35; i++) 

Don't use the same variable name...