Mary Penner, who uses a walker to get around, said she had been looking forward to the Games for a long time.
"I just want to forget the Games are on now," she told CBC News.
On Friday, Penner took an accessible Wheel-Trans vehicle to the opening ceremony, but security would not let her get out in the designated area documented in the Games accessibility guide, she says.
Once inside, she found out the accessible section she was supposed to be in was full.
Moved twice, lost view
Ushers moved her twice, eventually finding her a seat nowhere near the one her $150 ticket entitled her to.
"I was sitting watching the Olympic flag and the Pan Am flag come in with [Canadian Paralympian] Rick Hansen as one of the flag bearers and I couldn't even see because everybody stood," she said.
She said she's used to dealing with accessibility issues, but wasn't expecting it from the Games.
"They have all these things all over their website saying how great it's going to be for accessibility, and then they screw it all up."
Toronto 2015 CEO Saad Rafi says accessibility is one of the Games' top priorities.
Pan Am Games officials contacted Penner immediately after CBC News told them about her situation. They say they want to know exactly what happened so they can fix any accessibility problems before the closing ceremony.
Penner says she bought hundreds of dollars worth of Games tickets and wants a full refund.