if it makes u feel any better, i just recently rma'd a 64gig corsair set, and they sent the replacement set out on monday and i got it this morning like 32hrs later. they shipped it from the factory in tiawan. if i didn't know any better, they must have paid like 100-150 usd for the shipping alone for 3 air hops to me. corsair has a 5yr warranty and my set was like 2yrs old when i rma'd it.
but back on to topic, u have 2 options - 1 . get another set for the one already in the unit from the same maker with same specs, or 2. replace the whole memory selection with same or different brand..but make sure it's same type of ram(dimm ddr2/ddr3/ddr4 or sodimm ddr2/ddr3) to be compatible with your unit