My employer assigned me to a HSA on accident, I contributed 6750. My employer then backdated healthcare plan to be an HRA. I withdrew 6750. How do I handle this?

I had a life change event last year. When the life change event occurred, my employer assigned me to a HDHP and I contributed 6750 to the HSA.  My employer mistakenly assigned me to this plan.  I wanted a HRA that was not HSA eligible.  After talking with my employer, they back dated my healthcare plan so it would be the HRA the entire year.  Once this happened, I closed my HSA and withdrew all funds - 6750.    My W2 list 6750 in the 12W box.  How do I pay taxes on this amount but not face any penalties???

My Deductibles and OOP Max were resetting mid year with the HSA so that was not the best choice.