A small crack that leaks little I would not worry about to much,
repair it to see if that is all you need, company B & C are just selling
Repair it yourself but the prep is 99% of getting a bond that will
last. Open it up with a chisel or grinder so you have depth you can
access to remove loose material and clean out all dirt and mold, 1-4",
Just don`t do a quicky surface repair . You need to get it cleaned out
first with a brush, then hose it out. Use bleach to kill mold, sqiirt it
in with a meat baister. Muriatic acid [ dangerous and fuming] squirted
in the crack with a meat baster will remove dirt, and etch it. Depending
on size and depth of hole, hydraulic cement, mortar mix, epoxy or
special caulk can be used .
If you hire it out remember prep is 99% of the job, it is not a 5 min
job, it must be clean and solid.