I know how frustrating that is.
I went to stay at a friend's house and took my daughter in a bumgenius OS which I placed in a nappy sack for safe keeping We had disposables for overnight... I got home the next day to discover the washable had disappeared!
I rang my friends up and made them get the nappy sack out of their bin and return it to me
I was gutted to discover the nappy sack only had a disposable in it (I didn't dare tell them that though!
) so I think my husband threw it away when we stopped on the way home
I was gutted and furious for days but you have to let it go otherwise you will DRIVE you MAD.