Adultwebsites

Yes, I know this was stupid, but I genuinely didn't think this would happen...
I set up a fake landing page for an adult website. It was intended to be a joke for a friend, was only up for a couple of weeks, didn't charge any fees, didn't post any copyrighted material, and any reasonable person should realize it wasn't actually related to the company. I can't imagine it got more hits than you can count on two hands, all of which were from me and my friend (and the lawyers).
I believe the potential trademark infringement comes from the URL; let's say the real website is www.adultwebsite.com and I purchased the domain www.adultwebsite.info
A couple days ago I received a cease & desist letter from their attorneys and the domain registrar was also copied on the email. While the letter was sent to everyone, it doesn't single out a specific name or organization in the salutation.
The letter asks for the following things to happen within one week:

• Disable the domain & website
  
• Forward the domain from adultwebsite.info to adultwebsite.com
  
• Transfer the domain to the trademark holder
  

I took the site down right away. Then the registrar locked me out of the domain so I can't set up forwarding or take care of the transfer. I emailed the registrar and asked them to help me and their answer was basically told that only the trademark owner can request these things. I let them know that they were copied on the C&D email but they gave me the same reply - only the trademark owner can request these things.
So here I am with a demand letter but without the ability to fulfill the demands. I emailed the paralegal that sent me the letter explaining the conundrum but haven't heard back.
What can I do here? Will the domain registrar likely take care of the above items? I know I made the landing page and bought the URL but can I really be sued for not meeting their demands when I'm not being allowed to meet their demands? I can't imagine there are any damages at all but I'd rather not spend a lot of money having to prove anything.

My girlfriend, Sarah, and I have been dating for 9 months. We met in Argentina, which is our native country.
When I met Sarah, she was still dating her ex, Gabriel. They had been dating for 2 years and lived together. She cheated on Gabriel with some other guy, met me and we decided to go on a European trip together. Currently we are living in Berlin.
Before Gabriel, she dated two guys who were a bit weird. They would contact the guys she saw after ending things with them etc.
Anyway, we have been dating for 9 months and it is great. However she seems to think that her ex (in this case Gabriel) can’t live without her. He hasn’t contacted her since they broke up, yet she is convinced that he created a subscription for her on some adult websites.
She got a mail a month ago saying ‘Thank you for subscribing to ‘adultwebsite’. There was nothing on the account. So it seems that it was just some spam.
Yet she has been convinced it was him. She can’t stop talking about it.
When we started dating, her ex forwarded her some mail that still came for her on his home address (it was some letters from her bank)
She keeps obsessing about it? How can we solve this?
Tl;dr: GF is obsessing over her ex? What to do ?