There can be various reasons why the shops that you were emailed about are not on the Available Shops page.
-Some shops have specific requirements such as age or gender, and if you do not meet those requirements, you will not be able to see the shops on the Available Shops page or do them.
-Some shops are posted in large numbers, and when a certain limit of scheduled shops is reached, the rest become "hidden" from the Available Shops page, as no more can be assigned.
-Some shops are in very high demand, and it happens that they are already picked up by other shoppers by the time you login and check the Available Shops page.
-Sometimes Mystery Shopping Providers restrict shopper profiles from accessing their shops, in case they do not wish to work with a specific shopper, and in that case all shops from that MSP will be hidden to that shopper.
In any case, for the most accurate information about any shop's availability and/or reasons why you might not be seeing some shops, please contact the MSP that posted them, and their schedulers will provide you with answers.
Thank you for asking!