Where to buy a digitizer for this iPod touch.

I recently purchased a digitizer fully assembled on ebay and to my luck didn't work. I contaced the seller and he gave me a new one for free. I thought that was pretty cool. Anyways, the new one came the other day and up until now I managed to test it out. It still doesn't work.

Either the supplier just has faulty digitizers or it's my ipod.

My questions is, where can I get digitizers for this ipod and it guranteed to work properly? And also at a reasonable price.

I'm really wanting to fix this ipod. I an wanting to fix them for my costumers and want to give them reasonable prices.