Hello, solocazzimiei and welcome to the Monastery. It is quite difficult to read your code in this post and it would help considerably if you could enclose each section of code within <code>...</code> tags.
While it is not entirely clear what you actually want here, you can use many techniques to separate a key from a value based upon the first colon. Since you are using a regex anyway, here is one such.
use Test::More tests => 2;
my $in = "NOTE;ENCODING=QUOTED-PRINTABLE:=0AAddress:=0A=0Aor. Soroca=0
+ARepublic of Moldova=0A=0A=0A=0A Footwear. =Children's footwear. Lady
my $want_key = 'NOTE;ENCODING=QUOTED-PRINTABLE';
my $want_value = "=0AAddress:=0A=0Aor. Soroca=0ARepublic of Moldova=0A
+=0A=0A=0A Footwear. =Children's footwear. Lady's footwear.";
$in =~ /^([^:]+):(.*)/;
is $1, $want_key, 'Key matches';
is $2, $want_value, 'Value matches';
Equally, you could use split or even index and substr to achieve the same end.