Why jump through all those hoops? On the face of it all you need is:

#! /usr/bin/perl env
use strict;
use warnings;
use Data::Dumper;

my %record;
while (my $line = <DATA>) {
    chomp $line;
    
    my ($key, $val) = split /:\s*/, $line, 2;

    $record{$key} = $val if defined $val;
}

print Dumper (\%record);

__DATA__
Name: Sam
Address: Mascot
Ph.No: 123321
[download]

Prints:

$VAR1 = {
          'Ph.No' => '123321',
          'Address' => 'Mascot',
          'Name' => 'Sam'
        };
[download]

Note though that I added a chomp (most of your values would otherwise have a trailing new line), limited split to finding two elements to avoid chopping off the end of any value that happens to contain a colon and check to see that there is in fact a value field on the line.