Mpc x- possible sound card issue?

Hey everyone,
I just bought an mpc x from eBay and when I hooked it up to my studio monitor the sound was very wacky. The only thing that I could hear consistently when I hit the pads was when I would hit a cymbal pad. I then hooked up my earphones, in case it was a speaker issue and the same thing happened. Has anyone else ever had this problem? I bought it off eBay for $1200 and the guy swears it worked for him, now he’s offering a partial refund of $300 because he spent the rest of the money and I’m trying to decide if this is something I can fix or not. I saw that guitar center was listed as a repair place but wanted to reach out on here to see first if anyone has ever had this problem. Thanks in advance

if you initialized your X when/after first use
and other sounds/instruments sound OK through your studio monitors
(through the same inputs!)
then this sounds as a Dfect
would insist on full return then

A partial refund of $300 after you spent $1200 on it? Nah if the product doesn't work, he needs to refund the whole amount. A $900 'try before you buy' fee to find out its not working would get you hurt here.

If the seller sold you a product that doesn't work as advertised, he needs to refund the full amount, not 1/4 of it. Contact eBay and file with them. If they decide in your favor, they will MAKE him pay, in fact they will TAKE it from him and he has no say in the matter heh. Hopefully you did it via PayPal..