The company profits fell off this month because of lack of sufficient employees in the company. Fine
This accounts for the fell through of the loan sanction with the bank as our company profits not enough to meet the minimum requirements of the bank.
This sentence is incorrect.
"The company profits this month were not enough to enable us to meet the minimum requirements of the bank for the repayments on the loan."
To use "fell through" >> The repayments on the loan fell through the cracks as the accountants did not make allowance for them.
In this context, "fell through" would be used in form of the idiom "fell through the cracks", meaning no-one noticed that there was a mistake.