I passed so many test at home when I never once tried to dilute my urine just went through may day as normal, and then finding out that I failed the labs initial screening.
If your account is indeed true, not only youve failed the initial screen, but youve failed the confirmation GC/MS as well. You were provided a quantitative value (62 ng), which is a clear indicator that the confirmation GC/MS was performed.

If you are close to the 50 ng/ml level but still over by 15ng or so, could you dilute by not doing do much to alter the specimen? such as drinking large amounts of water, taking vitamin B pills, and such.
Drinking large amounts of water causes the urine specific gravity and creatinine levels to take a nosedive, resulting in a "too-dilute" ruling. Therefore, when going the dilution route, it is important to keep tabs on your creatinine and S/G. This can be done by testing the creatinine and S/G with a validity test strip. These kits are essentially the same as the ones used by the labs when performing integrity checks. They are found online by doing a Google search for "drug adulteration test kits".