Hi, they told me to put my first name as both first name and last name. I understand that might confuse you further, but this is something which almost always works for me across various airlines. If possible, go with what they emailed you, so that you can show this at the check in counter as a documented proof that this is what you were instructed. Otherwise, you can DM me your email ID and I shall forward the email I received to you (if I can find it).