If an ampersand is included in the customer's email address, the following error is returned during createTransactionRequest: Extra Options is invalid.
I cannot find any other post about this issue, so any help would be appreciated.
Replying to an old post so that it can help someone..
You need to url encode the email to handle the special characters line &, + in the email..
for + it would be %2b and for & it would be %26
so, firstname.lastname@example.org would become someone%26else%2b123%40email.com
this works fine to show the email in the hosted payment page and the email receipt is sent to the email..
but, in the email the characters are shown as spaces :(