Gemini is a legit exchange and I don't think that they'll just take your money. If you haven't heard anything from them, you need to contact them again with another ticket and through other means of their contact whichever is indicated on their contact us. They have FB, LinkedIn, Instagram and Twitter aside from the ticket. Email them too at
support@gemini.com.
I just emailed them using that email you provided and also FB them, hopefully I hear from them.
Hopefully and let's be positive that they'll respond to your email. I haven't used them but knowing that the owners are the most popular twin in the crypto scene, they should have good customer service.
A reply with that problem of yours will be much appreciated. Keep us updated.