Well, when choosing ram, the main thing is to choose a single kit of the capacity and speed you want. When you go mixing ram kits of the same specs, you're just asking for complications.
Ok, so you were able to get 4133MHz stable with 1 kit?
You can try the other kit, but don't be disappointed if it doesn't want to run at 4133MHz, you may have to settle for a lower frequency with all four sticks.
Shut down your pc, kill the power and add the other two sticks, keep the same settings and start with Dram Frequency 3600MHz.