Russo had threatened to put the Championship club into administration - triggering a 10-point penalty - after refusing to defer the loan's repayment.
But Russo accepted a deal on Friday which ensures the club's future.
"I'm relieved to have all this sorted out but it's disappointing it has taken so long," Russo told BBC Radio 5 live.
"It has rescued the club and it is good for the club and I'm delighted. I didn't want to put them into administration.
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