I paid for item but seller deactived their account as soon as I paid. What should I do?.

[carlimooks435970]

 I paid for an item. But as soon as it was paid, ebay messaged me saying that they had to cancel the listing, not stating the reason. I tried to message the seller but they're account was deactived as soon as I paid. The item was paid for I'm positive of that and I don't know if I should open a case right away or wait for awhile. My question being ; what is the amount of time should I give the seller to see IF the item in question will come?.