Just some info, any problem with a PC no matter what can be memory related. The reason being that every single operation performed by the CPU and all hardware connected rely on the memory (RAM). An error message such as "INACCESSIBLE BOOT DEVICE" doesn't mean much on it's own as for instance if your SSD drive is using a portion of RAM that is faulty it might show the same error. In this example anything that alters the SSD operation and causes an error may cause the above. (The list is big, SSD connects to the motherboard, this goes to a controller (chipset), that talks to the CPU and they all interact with the RAM direct, so anything in this path could be at fault)
Your memory and SSD test in the BIOS don't actually test anything, they simple see if the memory or SSD is responding / accessible. A full memory test would involve a program writing data to each memory location in various patterns and recalling the pattern back, the source pattern is then compared to the written / retrieved data to see if it is altered. (this is a very basic explanation), this process will take over 30 mins or longer with more RAM.
SSD test is also of a similar nature and if the entire drive is to be tested it would take much longer.
Anyway, yes I think you should send it back as it's not working correctly.
