If you ever have any problems with your Internet connection, you'll need to put a call into your Internet service provider (abbreviated as ISP). You will be able to speak with a customer support technician and describe your problem, at which point this person will either guide you through the process of fixing it or send a repairman out to fix it. If you don't know the telephone number of your ISP, you can find it in a few places.
Look on your monthly billing statement, as well as any other correspondence you get in the mail from your ISP regarding your account. Any information that comes in the mail from your Internet service provider will always have that ISP's telephone number printed on it. This is done to make it easy to find if you have a question or concern in regards to the bill or piece of information you just received.
Use that Internet service provider's website. The telephone number of an ISP will always be on that company's website as a benefit to both new customers who may wish to sign up for service and existing customers who can't seem to find their monthly billing statements to locate the ISP's phone number.
Use the phone book. You can search for businesses in the phone book by either category or by name, so as long as you know the name of your Internet service provider and have a phone book lying around in your home or office (or can get one), it shouldn't take more than a couple of minutes to locate your ISP's phone number using this method.