I would guess it would work as if it wasn't redirected at all. The sending server would try to resend for several days before bouncing it back to the original sender. I could be wrong and if I am someone please correct me.
There are many DNS server scattered through out the world. Each of these servers maintains records of where your domain name is located. It takes 24-72 hours for all of these DNS servers to be udpated.
What is the domain name?
Unfortunately you must not have transferred it. You can go to http://www.internic.com/whois.html and enter your domain name. It will show dotregistrar.com as the current registrar.
Your domain name registration is separate from your hosting contract. I'm sure your site is still on the TCH servers but your domain name has expired.
You will need to contact dotregister.com to renew your domain name.
Not saying there isn't a problem just a reminder. Although you have a connection to the FTP server the packets still have to travel a path to get to the server from your machine. If something slows the packets down along the way timeouts can occur.