For the Nokia 1616, legitimate services on eBay or dedicated unlocking sites charge , not $30. They look up the code in a database rather than "calculating" it live.
The Nokia 1616 is a vintage backup phone. If a $2 unlock code from a reputable seller doesn’t work, it is likely cheaper to buy an already-unlocked used phone than to chase dangerous "calculator" downloads. Nokia 1616 2 Unlock Code Calculator - Updated Hit