Without pictures it is really hard to say for us. There are a variety of reasons why cacti growing out of their natural environment will show a different growth habit. For example comparing Ottawa to the ultra dry coastal and high deserts where Copiapoas naturally grow would suggest there could be temperature, light, and humidity/moisture issues.
Most cacti will start growing long and stretched when bereft of enough light - I am actually seeing that with a couple of Copiapoas that I am growing here in Mesa, Arizona - the sun is so bright here that they are not that happy so I gave them a lot of shade - too much... I will try and post a picture tomorrow as I will not be home until late tonight.
