Anyway to recover my friend and I's server?

Me and my friend had a hardcore server going but then we decided to change it from hardcore to normal Minecraft and after logging in the entire server had been reset. We've restarted it a couple times but nothing has come back. We had this a while back on an old server where the nether reset and came back after a day or two, will the same happen now or is it entirely gone?

That's a shame but thanks anyway.