Following a game update yesterday the entirety of Old School RuneScape was inaccessible. All worlds were official taken offline at 12:41PM, however issues actually started prior to this time. Some worlds crashed instantly, some were taken down intentionally with short or no warning given. This means players could have been in a stake, or in a PvP/PvM situation at the time, and they could have potentially lost their items. This is clearly a very serious issue, however Jagex announced they would not do a rollback as this would disrupt the game in a larger way, instead what they have opted for is to offer any affected players a chance to submit a claim and request reimbursement.
If you lost items due to this issue, you must submit a claim prior to April 2nd 12:00AM GMT. Claims can be filed via:
Before you go, they have stated that any false claims will result in action against your account, we expect - at minimum - this would be a temporary ban. Do not abuse this. They will be able to see what items you had on your account and therefore be able to establish if anything was truly lost. For example, if you sold something on the G.E and expect you may be able to claim this back (sneaky sneaky) -no. They have logs for this. Submit a completely truthful claim only.