Good afternoon eliza,
The MSN WAP/SMS Services are activated by the customers themselves via the MSN Web site.
MSN Mobile and Instant Messaging are two distinct services, where MSN Mobile is an alternative, through text messaging or GPRS, for customers who wish to use MSN Messenger but do not own a compatible handset.
Fido Instant Messaging provides customers with an application available directly on their Fido handset which is similar to using MSN Messenger on a PC.
As provided here, you may be able to stop those from reaching you.
Hope it helps.