Unlike a normal call, part of the call charge is paid to the service provider, thus enabling businesses to be funded via the calls.
While the billing is different, calls are usually routed the same way they are for a toll-free telephone number, being anywhere despite the area code used.
These telephone numbers are usually allocated from a national telephone numbering plan in such a way that they are easily distinguished from other numbers.
You have exceeded the time limit and your reservation has been released.
The purpose of this time limit is to ensure that registration is available to as many people as possible.