Ok, but leicester can't use a rumour as a basis of an official complaint. There will be lawyers involved. They'd need evidence. Or just be laughed at.
Also agreeing personal terms does not mean a contract has been signed.
Who is suggesting they use a rumour for an official complaint? Of course they need evidence, the point is if that's what is what has gone on - Chelsea talking to Forfana to the point that they've agreed terms - then Leicester would have grounds to do so (if they have any evidence, for those at the back)
Also agreeing personal terms is prerty well known short hand for the clubs people talking to the players people and agreeing everything in principle wrt contracts and just waiting to sign.