Dual SIM

Hello, I recently got a new work phone which is the iPhone 13 and it came with the dual sim so essentially, I have two numbers. My primary number was my original phone number. I can only receive calls that come to the secondary number. Anyone who calls my primary, it goes right to voicemail. I did all the checks I found online...no block callers, do not disturb is off. Any ideas on how I can get calls back to my primary number?