Item not received allegidly

[kevelama]

I have sold a pair of bnib boots to an untrustworthy (in my opinion) ebayer and he is saying item not received,,Unfortunately  i have tracked parcel and it states still in transit , although most of my items say still in transit despite getting feedback, I have contacted royal mail and although they under stand that there has been a problem with their tracking system there is nothing  they can do, I have stopped 3 of this persons accounts from bidding on my items due to his underhand buying and selling practises and i didn't realise this was another of his accounts untill i saw paypal details whitch was too late as i had posted, I may be being a bit suspicious but if he has my item he can use tracking details attatched to parcel  and see the results, I guess i am onto a loser unless anyone has any ideas, Thanks,   

Obviously no way out for me then,     How can a buyer/ seller have so many accounts and stitch up so many ebayers, and get away with it  with a load of lies, I now know of 4 of his accounts but at great cost,