Every year from 2003 to 2006, Jose Sicajau made the trek from Guatemala to Canada, working at a produce farm south of Montreal to earn money for his family back home.
One day, he and fellow migrant workers were building an irrigation system on the operation.
Mr. Sicajau says the owner, upset that they were doing the job incorrectly, hit a Mexican worker in the foot with an aluminum pole.
He and two other men signed a written account of the incident and filed it with a local union.
Since then, no employer in Canada has invited Mr. Sicajau back.
In Guatemala, he formed an organization of fellow ex-workers to press governments to raise standards in programs such as Canada's Seasonal Agricultural Workers Program.
This week, he returned to Canada as part of a delegation of Guatemalan activists, to meet with current migrant workers and bring their concerns to civil servants and politicians.
"If we want to get ahead, we have to find work [outside of Guatemala], and that makes us quite vulnerable to people violating our rights," Mr. Sicajau told The Globe and Mail through an interpreter.
One of the workers' chief concerns is the fact that the program ties them to a single employer.
If they quit that job while in Canada, it can take months for another company to go through the paperwork necessary to hire them.
As a result, Mr. Sicajau says, workers put up with poor conditions.
"There should be on-site visits to the places where workers live, without the farmers knowing in advance," said Father Juan Luis Carbajal Tejeda, a Guatemalan priest who belongs to a Catholic order that helps migrants.
In most streams of the program, workers do not have any direct way to become permanent residents or Canadian citizens despite working in this country for many years.
They also miss out on many of the government benefits accorded to Canadians.
Winston Morrison, 37, a migrant worker who met with Mr. Sicajau in Windsor, Ont., this week, said he is facing exactly that problem.
A Jamaican national, Mr. Morrison said he has come to Canada every year since 2004 to work at a farm near Leamington.
Last year, he injured his right knee in two separate falls and said he had a metal plate put in it.
Over the course of the winter in Jamaica, his leg became swollen and painful.
When he returned to Canada in May, Mr. Morrison said, his condition was so bad the leg had to be amputated. He is living with a friend now, unsure how he will provide for his family.
"These governments, they don't know what we're going through," he said.
"We are treated like we are nothing."
The Guatemalan group met this week with officials from Ontario's Ministry of Labour; next week, they will meet Quebec civil servants and members of parliament in Ottawa.