WHich One I need use? AP or I-94? I just Landing in Vancovour, b

have no chance turn in my I-94 and my hu*****and's. so I-94 are still in our hand. My hu*****and Got his I-94 when he came back using AP, I got my I94 when my H4 was approved. So there are different. Could we use the I-94 go back USA after 3days? We planed AP go back USA with AP, but we have nowhere to turn in I-94? please give suggestion. Thanks