DDMM_C1 & C2 Issue

Hello guys! About 8 months ago, I've brought my brand new PC from pc-specialists and now I've came across a slight problem.
I noticed that system information is telling me that I have only 48GB of DDR4 ram installed even though I have 64 in reality. Then I double checked this with CPUZ only to find this:


I diagnosed my problem by:

-Swapping ram from block C to block D and inversely for D to C.
-Tested each individual ram (by placing it in block c)
-Ran memory diag

From this, I concluded that there must be a problem with DDMM_C1 and DDMM_C2 as none of my ram sticks work there.

Do you guys have any ideas / suggestions of what the problem could be and how serious it is?
More photos below:
View attachment 6732

Your screenshot of CPUz shows 64 GBytes which is odd if two of the slots aren't working.

If you've concluded the slots on your mobo are not working I'd consider getting in touch with PCS to see what they think - it is likely grounds for RMA (assuming your warranty is still active).