I am not aware of a way that the employee can call Service Canada. I would think you need the file number to be able to get any information and only the employer would have that.
I would be wary of an employer that isn't interested in finding out what is going on. They may truly not know what is taking so long, but in the interest of getting you there and starting work, they should call to find out the status of the application. Hopefully not, but perhaps it got lost. If the employer never calls you could be waiting indefinitely. Good luck to you!