Perhaps they are not compatible. Did you not think about this ahead of time?
Great headset and mic deals are out there. Why did you want separate units?
Why USB?
What is it you want to do?
Standard units for PC costs less than $20 or up to $70 for pro.
... image from Amazon. under $25.
Amazon Headset with MicThis thing has both double earpiece and mic together and is a popular choice for many users. It has to work, or edlse they would not sell it.