Legal Question in Civil Litigation in Washington

It depends on the cause of action you want to bring against the phone company. A breach of a written contract has a 6 (six) year statute of limitations, which may apply here, assuming you have a written contract for placement of the ad. If it's an oral contract, it is 3 years. Libel has a two year statute of limitation. Most other tort actions have a 2 or 3 year statute of limitations, depending on the exact cause of action you sue for.

If you are interested in reading up on this, google the Washington State Legislature's website and from there, you can lookup RCW 4.16 and each subsection for the specifics. Best of luck to you.