How do I fix my Cookworks 4 slice toaster?

Since my wife tipped the toaster (Model No. 131821) upside down to clean it, our toaster won't hold down on one side. I've had this problem before on similar toasters where bread (toast?) crumbs get stuck on the magnetic plate inside and stop it working, but I've always been able to get them apart to clean them. I don't seem to be able to get this one apart, can anyone help?