Telecom's broadband signal is not good, how to contact their maintenance personnel?

Telecom's broadband signal is not good, how to contact their maintenance personnel? When the broadband of telecom is installed, the maintainer will give you a maintainer's phone number after installation. If you don't keep it well, you can call the customer service phone of the telecom company, 100000 to contact them, and they will ask to serve you.