“I’m going to dispute because I’m afraid of the ding to my credit.”

No offense, but what exactly is your basis for disputing it?

Assets – Liabilities = Owner’s Equity

Accounting 101 my friends.

Asset values fluctuate and debts do not…the result is a change in Equity.

You only had the LOC at the bank’s discretion for risk. They can take it away whenever they want.