Column C is the amount of Premium Tax Credit you received each month towards your Premium Cost in Column A.
If you believe your 1095-A's are incorrect, you need to contact Healthcare.gov.
All we can do is provide general information about 1095-A and Form 8962.
It sounds like you may need to go over the income, family, etc. info that was provided when you first got your policy.
Here's How to Enter Form 1095-A and How is the Premium Tax Credit Calculated.