The formula that I gave can be shortened to the following which finds the starting point of the first number in the text string and returns 12 values. This of course will not work if there is some other number before the telephone number if a telephone number isn't found with "phone" preceding it:

Formula: copy to clipboard 
=IF(ISNUMBER(SEARCH("phone",A1,1)),MID(A1,SEARCH("Phone",A1,1)+7,12),MID(A1,MIN(FIND({0,1,2,3,4,5,6,7,8,9},A1&"0123456789")),12))