Unable to fix negative COGS due to adjustments in inventory module ?

SUGGESTED

We are a factory using Sage 50 Quantum. We use average cost and quantities were not negative. 

I managed to set the correct quantities and values of the inventory by using the inventory module, by first resetting the value to 0 in the module and then adding the correct quantities and values. 

I believe this caused the COGS to become incorrect as it is now highly negative. 

Any help on how i could proceed to have a correct COGS would be highly appreaciated. 

Thank you, 

Kevin