hi and whats wrong with my U-MIX44??

hello to you all like minded people!!
I'm an older DJ that peaked at free parties and some small venues around the turn of the century. (sounds years back saying it like that) I decided to go MP3 with your product (DVS Ultimate).I maybe get on to my decks 2 times a month now so i have spent since Xmas trying to get a clean sound out of the software. i have now replaced my mixer, laptop, needles and even borrowed cables and decks of people to sort this problem out. I cant get a clear sound out of my system and never have since i got it at Xmas. i have realised that its the U-MIX44 box that is at fault.
Please can someone advise how i get this sorted under guarantee. I got from e-bay from some big company i cant remember off the top of my head.
Thanks to anyone who takes the time to read it..
Crinklee..
I'm an older DJ that peaked at free parties and some small venues around the turn of the century. (sounds years back saying it like that) I decided to go MP3 with your product (DVS Ultimate).I maybe get on to my decks 2 times a month now so i have spent since Xmas trying to get a clean sound out of the software. i have now replaced my mixer, laptop, needles and even borrowed cables and decks of people to sort this problem out. I cant get a clear sound out of my system and never have since i got it at Xmas. i have realised that its the U-MIX44 box that is at fault.

Please can someone advise how i get this sorted under guarantee. I got from e-bay from some big company i cant remember off the top of my head.
Thanks to anyone who takes the time to read it..

Crinklee..