Bell spokesman Mark Langton wouldn't say how many jobs were being cut at the Mississauga call centre or how many were being added at the other two locations.
"Bell is focused on improving customer service at every level, and late service hours and better bilingual service are part of that," he said Thursday.
"Growth at these two centres is balanced by some reduction in positions at the Mississauga call centre."
The Toronto Star reported that Bell Mobility employees were saying that between 300 and 500 workers would lose their jobs at the Mississauga call centre.
Bell Mobility call centres help mobile phone, tablet and mobile Internet customers.
Kim Ginter of the Communications, Energy and Paperworkers Union of Canada said the union tried more than once to organize workers at Bell's Mississauga call centre, but was unsuccessful.
"I think there was some intimidation by the company," he said from Toronto. "We were very close and we weren't successful. Sometimes it takes a couple of different tries to convince people to join a union."
Ginter said it would be difficult to prove any relationship between the job cuts and the unionization attempt.
"These are hard things to prove if Bell is saying it's because of bilingualism and different hours in different regions," said Ginter, a vice-president of the union's Ontario region.
Ginter noted that a union presence would have helped workers deal with the cuts and their severance packages.
"One thing to soften the blow with layoffs is that unions are usually successful in working with companies to deal with those issues. Without the union, now these people will suffer exactly, I guess, what Bell decides."
In November, the union said Bell Canada was consolidating some departments, resulting in 52 union job losses in Toronto and Ottawa.
But Langton said Bell is adding to the ranks of its customer services and has hired about 1,000 new service technicians in the last year to support its Fibe Internet-protocol TV service in Toronto and Montreal.
The Bell Mobility cuts are part of a recent wave of layoffs in the Toronto area — including hundreds of jobs at the Toronto Hydro utility and at least 68 laid off temporarily by Montreal-based Garda World Security at Pearson International Airport. The union says 299 Garda workers have received layoff notices.
In Quebec, French drugmaker Sanofi-Aventis has cut 100 jobs in the Montreal area, while Johnson & Johnson shut down its research centre and laid off 126 workers.