Your Warranty is with eBuyer.
Now, to be clear here, your warranty is covered by the people who sold you the drive, not with the people who manufactured it.
The system of passing customers directly to the manufacturer is meant as a convenience for all involved (hah :), but does not reflect the way consumer protection laws work. If eBuyer asks you to contact the drive manufacturer directly for a warranty request, you are within your rights to refuse and ask them to deal with it themselves.
If eBuyer offered you a 5 year warranty, then you are entitled to one. eBuyer have clearly stated they will honour it, therefore goods are as described.
There may be nuances and practical aspects I haven't covered here, but that's the gist of it.