As long as you've followed the steps to unblock the caller from your phone then that should be that.... unless the caller has blocked you. 🚫
Block a phone number or contact on your Galaxy phone.
Try Settings, Apps, Phone, Storage , Clear Cache.
Once the caller / number is unblocked and you've checked they haven't blocked you then try > Clear Cache Files from the phone's System Partition Section > https://www.samsung.com/uk/support/mobile-devices/how-do-i-clear-the-cache-on-my-device/ You may need to insert your earphones or hook upto a powered On Laptop to access the Clear Partition Section. This may help with lag or stutters as this clears the phone of old/unused or broken cache files.There is also a Repair Apps option in the Menu System too.
Ensure the number isn't set to go straight to voicemail.
One of many links that may help > https://techwiser.com/ways-to-unblock-a-number-on-samsung-phone.
If I can be of any further help then please don't hesitate. Take care. 😎
Daily Driver > Samsung Galaxy s²² Ultra 256Gb in Phantom Black.
The advice I offer is my own and does not represent Samsung’s position.
I'm here to help. " This is the way. "