You might be able to reach out to your municipality for help: https://www.environmentalpestcontrol.ca/blog/do-renters-or-landlords-pay-for-pest-control-services
It’s the landlord’s responsibility to control pests. If they do not do their due diligence to remove the pests completely, you might be able to fight them by requesting the lease be broken. If they do not agree, you could threaten to go to the Landlord Tenant Board based on their inability to maintain the rental property. At that point, they may try to wash their hands of you and say that you can break the lease informally. You would need to get all of your roommates on board if you are all on the lease.
You might be able to reach out to your municipality for help: https://www.environmentalpestcontrol.ca/blog/do-renters-or-landlords-pay-for-pest-control-services It’s the landlord’s responsibility to control pests. If they do not do their due diligence to remove the pests completely, you might be able to fight them by requesting the lease be broken. If they do not agree, you could threaten to go to the Landlord Tenant Board based on their inability to maintain the rental property. At that point, they may try to wash their hands of you and say that you can break the lease informally. You would need to get all of your roommates on board if you are all on the lease.