I will slightly modify the first answer..
declare @phone varchar(50)
set @phone='212%@@f'
WHILE(PATINDEX('%[^0-9]%', @phone) ) > 0
BEGIN
--then remove that one character, then continue
SET @phone = REPLACE(@phone
, SUBSTRING(@phone, PATINDEX('%[^0-9]%', @phone), 1)
, '')
END
SELECT @phone