Is only happening to 2 numbers that can't call you? Have you checked your blocked numbers list? Are the phone calls from these two numbers going straight to voicemail?
Have you called your cell phone provider to make sure it's not blocked on their end? Also when blocking a call it could take 24 hours to process it being unblocked
If you tap the three dots in the Phone app, you can tap on Block Calls and then View Blocked Numbers. If you ALSO have a carrier-based call filtering app (i.e. Verizon Call Filter), you might want to check and make sure you 'Allow' those numbers to always ring through, and also check that they're not blocked in there too (it's supposed to block in both apps if you do it in Verizon Call Filter).
