Box 12b code W

On my W2 in box 12b I have a W with an amount that coincides with the same amount as on my last paycheck for supplemental insurance pre tax. I DO NOT to my knowledge have an HSA account. The only insurances that I have are my health, dental and vision which my employer pays for which is NOT a HDHP. And accident, critical illness, hospital, short term disability and life insurance through Colonial life. The amount deducted for my colonial life is what they are coding as a W in box 12b which I can't withdrawal funds from so I am being taxed on this as "over payment". Please help me understand this.