COLLECTON AGENCIES
I have a bank credit card in collections. A week ago the collection agency went into my account and withdrew my rent and car payment amounting to C$2000.00 and the cheques I issued were returned with NSF. I have limited income and just manage to pay my bills and in fact am one month behind in my rent. This action by the collection agency will result in me being evicted. Is this legal in Canada?

If the credit card they are collecting for was issued by the same bank that has your account then yes, they are within their rigths to go into your account and take a payment. It is called the right of set-off and as you have already experienced, it is rather unpleasant.
The only real defence is to switch banks – that is, make sure your bank account is not with a bank that you also owe any money too. Otherwise, thsi may very well happen again…