BUFFALO, N.Y. -- Although it was a huge success in terms of television and in-person viewership, Nik Wallenda's walk across Niagara Falls back in 2012 was not a money-maker.

"I lost money, a lot of money," Wallenda told 2 On Your Side Monday.

We reached out to the daredevil after hearing from the founder of a Toronto research company who said he was never paid $5,000 owed from that 2012 event.

Michael Harker shared invoices and email correspondence between himself and Wallenda's manager, Winston Simone.

After asking several times to be paid in full, Harker said in a September 26 email, "...been four months since we discussed the outstanding balance. Have you gotten your cash flow sorted yet?"

Simone responded: "Thanks to every person that we dealt with, Nik kinda, sorta, almost broke even... Virtually every company came to the party which otherwise would have been personally catastrophic to Nik."

Harker then told Simone that his company had already made a concession by only asking to be paid half of the money up front. He said in an email: "Sorry you are great guys but I feel ripped off here."

Simone then responded that all the companies had been fine not getting paid in full. "I am very surprised by your response," he said to Harker. "And honestly disappointed."

Harker told 2 On Your Side there was no further correspondence, and all these years later, Wallenda still owed him the $5,000.

"They just shamelessly stiffed us," Harker said by phone from his Toronto office.

2 On Your Side spoke with Simone and then Nik Wallenda himself. Nik explained that he made a "huge sacrifice financially" for the 2012 event. He said he regretted that Harker hadn't reached back out, because Wallenda does not have the financial ability to pay him in full.

Wallenda said he left a voicemail and sent an email to Harker offering to pay the remaining balance.

"I wish it hadn't come to this," Wallenda said by phone, just days before his wife will hang from a helicopter above Niagara Falls to mark the 5-year anniversary of Nik's walk. "I'm a man of integrity."

Wallenda said none of the other companies involved with the 2012 walk had any problem absorbing some of the losses, considering the final price tag was somewhere around $1.3 million. 2 On Your Side left messages with a couple of those companies, but never heard back.