match a part of a string using regex

Matching the single space can be updated by using a character class matching either a space or a word character and repeat that 1 or more times to match at least a single occurrence.

Note that you don’t have to escape the spaces, and in both occasions you can use an optional character class matching either a space or hyphen [ -]?

If you want the match only, you can omit the 2 capturing groups if you want to.

(PAI:[ \w]+<sip:)((?:\([2-9]\d{2}\) ?|[2-9]\d{2}[ -]?)[2-9]\d{2}[- ]?\d{4})@

Regex demo