Wireless Mouse [Logitech M510] Problems

So, hopefully someone can shed some light. I have two Logitech M510's. One came with a keyboard that I bought, and has not functioned well since I picked it up, resulting in moving to a 300 series mouse. A friend of mine got me a new one for Christmas, another M510. This time it worked reasonably well, but after a time, it started functioning poorly to a point where I had to switch out mice, back to the 300 series.

I took them both to work (both 510's) and plugged them into my laptop here and here's where the interest comes in. One works on a mouse pad, but nowhere else. The other works on only my pant leg. Neither of them worked on any surface I could find at home (cardboard, wood, mousepad, paper, pant leg, shirt). Yet, the other wireless mouse I had seemed to work just fine. Do I just need to get used to the idea that these 510's, despite how wonderfully the second one worked for me originally, are junk? Is there anything else I can try?

(They are both unifying, and I will be trying another unifying receiver for the laughs to see if it changes anything.)

Help?