I'm a Canadian lawyer. You do not have to pay. In fact, their sending you a notice like this is illegal. It does not comply with the notice requirements as per Canadian law.

Notice of claimed infringement 41.25 (1) An owner of the copyright in a work or other subject-matter may send a notice of claimed infringe- ment to a person who provides

(a) the means, in the course of providing services re- lated to the operation of the Internet or another digital network, of telecommunication through which the electronic location that is the subject of the claim of infringement is connected to the Internet or another digital network;

(b) for the purpose set out in subsection 31.1(4), the digital memory that is used for the electronic location to which the claim of infringement relates; or

(c) an information location tool as defined in subsec- tion 41.27(5). Form and content of notice

(2) A notice of claimed infringement shall be in writing in the form, if any, prescribed by regulation and shall (a) state the claimant’s name and address and any other particulars prescribed by regulation that enable communication with the claimant; (b) identify the work or other subject-matter to which the claimed infringement relates; (c) state the claimant’s interest or right with respect to the copyright in the work or other subject-matter; (d) specify the location data for the electronic location to which the claimed infringement relates; (e) specify the infringement that is claimed; (f) specify the date and time of the commission of the claimed infringement; and (g) contain any other information that may be pre- scribed by regulation.