If your soakaway is blocked up with sludge, grease, excrement and soil the worms will unblock it. They will not clear tree roots, or remedy crushed or collapsed pipes.
In 99% of cases the worms work fantastically, and 1000’s of worms have been sold up to date.
If the worms do not work, and you have to get your soakaway repaired or replaced, then all we require is proof that the pipes are not crushed or root infection wasn’t the problem.
Based on this will gladly refund you 100% guaranteed.