Contradiction with Ezekiel 29:18
Mention of Nebuchadnezzar's campaign against Tyre not yielding expected results, even after a lengthy siege, could be seen as contradicting the complete destruction implied in Ezekiel 26:21.
Ezekiel 29:18: Son of man, Nebuchadrezzar king of Babylon caused his army to serve a great service against Tyrus: every head [was] made bald, and every shoulder [was] peeled: yet had he no wages, nor his army, for Tyrus, for the service that he had served against it:
Paradox #1
Ezekiel 26:21 predicts the complete and permanent destruction of the city of Tyre. However, historically and archaeologically, the city of Tyre has continued to exist and was rebuilt after its initial destruction. This ongoing existence and habitation of Tyre might be seen as a contradiction to the prediction of it never being found again.
Paradox #2
The contradiction or conflict with Ezekiel 26:21 could be seen in the idea of God's punishment being very severe and final. Some people might think that a loving and forgiving God should always offer a chance for repentance and redemption. The verse talks about being destroyed forever, which might seem too harsh and unforgiving to some.