We do everything we can to catch common typos (like gmial.com), but we can't catch everything. Sometimes people just hit the wrong keys.
If your customer made a typo on a single purchase:
Go to the purchase
Click on “Email typo?” under the contact information
This will allow you to change both the purchase email and the Simplero ID email on behalf of the contact
Note: If a different contact already exists with that new email, the system will detect it and ask if you want to move the purchase to that contact. 
WARNING! - This will create a different Simplero ID linked to the new email. If your member has a Simplero ID that they want to keep, first they will need to follow the steps in this guide to change the email linked to their ID. After they do that, they will need to let you know so you can follow the steps in this guide and make sure they keep access to their content/emails.
Select Contacts from your Simplero Dashboard
Select All Contacts from the dropdown menu
In the Search field, enter your contact's name
Click on the contact, and you'll be directed to the Contact Info page
Click the Edit hyperlink as shown in the picture below
In the Contact info page, type the new Email address
Scroll down to the Purchase and participant info section and check all the places that the email address needs to be updated
Click the blue Save changes button!
Done! Your contact's email will be changed along with the billing and participant for all the purchases you selected and their Simplero ID.