I'm retired and get my health insurance partially subsidized by my former employer. I'm now self employed with net income. How much may I deduct on Sch C?

I'm being audited and the IRS auditor tells me I cannot take any Sch C deductions for the unreimbursed med premiums, because my insurance premiums are partially subsidized by my former company (I retired after 32 years and they partially subsidize the premiums). I still pay over $8000/yr unreimbursed premiums and as a small business owner, I can't take any deductions other than Sch A?