use warnings;
use strict;

my @chunks = <DATA>;
for (@chunks) {
    print unless /^(?:[*]|[a-zA-Z]|\d+\.)/;
}

__DATA__
1. For further assistance email us at 121@azing.com',
* You can also highlight any matter related to our Officer',
Page 2,
12345

[download]
prints: 
12345

[download]

Courtesy of YAPE::Regex::Exlpain: 

The regular expression:

(?-imsx:^(?:[*]|[a-zA-Z]|\d+\.))

matches as follows:

NODE                     EXPLANATION
----------------------------------------------------------------------
(?-imsx:                 group, but do not capture (case-sensitive)
                         (with ^ and $ matching normally) (with . not
                         matching \n) (matching whitespace and #
                         normally):
----------------------------------------------------------------------
  ^                        the beginning of the string
----------------------------------------------------------------------
  (?:                      group, but do not capture:
----------------------------------------------------------------------
    [*]                      any character of: '*'
----------------------------------------------------------------------
   |                        OR
----------------------------------------------------------------------
    [a-zA-Z]                 any character of: 'a' to 'z', 'A' to 'Z'
----------------------------------------------------------------------
   |                        OR
----------------------------------------------------------------------
    \d+                      digits (0-9) (1 or more times (matching
                             the most amount possible))
----------------------------------------------------------------------
    \.                       '.'
----------------------------------------------------------------------
  )                        end of grouping
----------------------------------------------------------------------
)                        end of grouping
----------------------------------------------------------------------

[download]

Also, here is an explanation of your regex, which might help shed some light on why it doesn't work as you expect: 

The regular expression:

(?-imsx:[^\d+\.?\*?])

matches as follows:

NODE                     EXPLANATION
----------------------------------------------------------------------
(?-imsx:                 group, but do not capture (case-sensitive)
                         (with ^ and $ matching normally) (with . not
                         matching \n) (matching whitespace and #
                         normally):
----------------------------------------------------------------------
  [^\d+\.?\*?]             any character except: digits (0-9), '+',
                           '\.', '?', '\*', '?'
----------------------------------------------------------------------
)                        end of grouping
----------------------------------------------------------------------

[download]

Update due to Animator's observation.

In reply to Re: regex to match words and numbers by toolic
in thread regex to match words and numbers by doubledecker

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