Can an employer keep health insurance premiums deducted from pay if coverage was not provided?

I recently had a Qualifying life event (QLE) and notified my employer within the 30 after event took place. I was expecting to receive a refund for any premiums that were deducted from my paychecks after the QLE occurred. I had no claims to the plan after the QLE, and was already covered on a new health insurance plan.

My employer has refused to refund the premiums collected, starting that the cancellation did not go into effect until after they verified the Qualifying life event (QLE). This is inconsistent with what I was told by our benefits administrator and has been hard to find in any of plan documentation.

I’ve verified with the insurer that and have documentation that the coverage was in fact retroactively cancelled effective the date of my Qualifying life event (QLE). So I had no coverage for the 30 days my employer collected premiums from me. Is this legal? My employer is based in NY. I’ve been going back and forth with our benefits Dept of Months and getting no where.