I am Pakistani with medium skin tone. Why is laser hair removal not working for me? I've had it for 3 years. (Photo)

Laser hair removal works as follows: the light emitted by the laser is absorbed by the brown pigment in hair.  This causes the hair to heat up.  The hot hair transfers heat to the cells around it that form the hair.  After a series of treatments, the hair becomes thinner, lighter, and eventually - gone.
Laser hair removal takes a series of treatments.  In some parts of the body you can achieve complete or nearly complete hair removal: the underarms, bikini line, and lower legs (below the knee).  In younger adults, particularly women, 8-12 treatments may be needed.  Women who are a bit older may need 6-8 treatments.
Areas that are more stubborn (need more treatments) are the forearms and upper legs.
Areas that require significantly more treatments are the male back and chest, or any area where the hairs are very thin before treatment.
In addition, laser treatment needs to be performed with more gentle parameters in dark skin, to reduce the risk of burns.
But - there are two additional elements at play.
First, hair growth on the face may have a hormonal component.  If so, the hair will continue to grow so long as the hormonal trigger for growth is in place.  Tests can be performed to assess whether this is the case.
Second, there is a phenomenon called paradoxical hair growth.  It is observed primarily in young women, with olive complexion, and on the face and neck.  For reasons not entirely understood, up to 10% of women undergoing laser or IPL treatment for hair removal in this area may have paradoxical growth of more hair.  If this is the case, further laser hair removal is not likely to be beneficial.

There can be hormonal issues that make laser hair removal more difficult but assuming that isn't the case, the LightSheer Laser usually doesn't have burn earlier in the treatment cycle. If you/they categorized your skin type wrong that might be a source of your problem.