Pixel 3a can't receive calls but text and data work

I have a recently purchased, unlocked Pixel 3a. Data and texting work fine, but I can neither place nor receive calls. Occasionally a call will come through, but the person on the other end can't hear me speak. sometimes I am able to place a single call right after restarting the device, but subsequent calls fail.

I have spoken with support a couple times already, and confirmed that my SIM card is fine by testing it in another phone. I have also manually entered APN settings according to Cricket's instructions.