it's an abbreviation for British exit, it refers to the possibility that Britain will withdraw from the European Union.
Telecom Domains are a web based company who offer domain name registration, hosting and other web services. You can find out more about them here. If you contact them they should be able to answer any questions you have.
Telecom Billing is a process of collecting usage, aggregating it, applying required charges and finally generating invoices for the customers. Telecom Billing process also includes receiving and recording payments from the customers.