External Speaker Trouble

Hi! I have a set of Logitech speakers that I use as my external speakers for my 2008 Aluminum body MB. Recently, I plugged in the extension cable that connects the two into my Audio-In Input (circle with two triangles on the sides) and used it to record a song through my amp. When I went to plug it back in to the headphone port, I no longer had sound.

My Macbook recognizes that there are speakers plugged in. They show in the audio settings and nothing is muted in the MIDI setup either. And they are selected as the output source. I also tried a NVRAM/PRAM reset, compressed air and everything else I could find still to no avail. Does anyone have an idea as to why they no longer work?