Based on the above: You made a mistake by shortening your prayers during your return journey. What you should have done was offer the prayers in full, because the distance from the place where you decided to return to your city was not equal to the distance at which it becomes permissible to shorten prayers. And you have to repeat that prayer. And Allah knows best.

Shortening the prayers when travelling is a confirmed Sunnah that one should not forsake, according to the consensus of the imams (leading scholars).