That email rings all the bad bells in me. If it were teh UK the first port of call would be the Land registry - now an open record inspectable online for a very small fee, but not all leases and tenancies are registrable so even if the lessor owns it does not prove there is no prior right to occupy.

Secondly, there may be restrictions on underletting resulting from the ownership/head leasehold of the property. In the UK those should be discoverable from the Land Registry - but you are not dealing withthe UK.

Thirdly, will the "owner" not have a mortgage? In the UK these usually prohibit leasing (or underletting) without the consent of the mortgagee, so a breach could result in the owner suffering possession proceedings from the mortgagee.

Fourthly, the very use of "ebay" as a payment mechanism smells fishy. Does ebay offer payment facilities? I know its associated company Paypal does, but that is not the same thing.