@Cow That pattern may be a North American number. If it is, please use a format which starts with an optional 1 followed by possible separator text and has the main number in the format 818-350-8009 where - could be a single alpha character or any [\W_]*+. Alternately, you can add the comment (?#IS NorAm) to the end of the pattern to force also using the alternate normalized form, or (?#NO NorAm) if it's not a North American phone number and it's incorrectly recognized as one. Perhaps try !!/blacklist-number 818-350-8009. Append -force to the command word(s) if you really want to add the pattern you provided.
