Maybe s/he didn't read the instructions?
Have you used it? How is it working?

I was also given Voltaren gel specifically for my neck. It does help when it hurts but I also used if for other things now as well. However I was told my my sports medicine guy that if the problem is deeper it often doesn't work well. Only so much gets absorbed into the system. It hasn't helped much with my knee or deep muscle/joint issues.