Volume constantly going down

I previously had a Sandisk MP3 player, but not a plus, I accidentally left it in a cup holder that had water at the bottom over night, I then got a Sandisk MP3 player plus or whatever, and it said it was water proof, one day I noticed the audio would occasionally go to one ear. So I decided to try to clean the part that you plug your headphones into, I cleaned it with a bit of alcohol and water, next day the volume began to just go down and it would stay on the volume screen no matter what (Unless it was turned off), basically it was like I was holding the volume down button constantly.

Any idea if the MP3 player is still recoverable and usable or do I have to get a new one?

the player is not waterproof. it is IPX5 splash proof. If you had the headphone door open and put water inside the headphone port the water got inside and probably damaged the device. It is only splash proof of the door is closed and you are using BT headphones or if the headphones that came with it are plugged in to the headphone port as they make a splash proof seal.  

Opposite effect has just now applied, the volume is constantly getting turned up, and I can’t turn off the MP3 player unless I hold down the button even longer then usual