If your concerned about your credit score, I recommend paying the bill, keeping it current, and sticking out your contract commitment.
Credit scores are based mostly on current credit performance and length of credit history. There are other factors but those are the main 2. If you don't take care of this obligation, you will have the following on your report :
1. A delinquent payment account thats more than 150 days past due eventually
2. An account that has went to collections
3. Possibly a charge off, and a judgement if they sue you.
All of these things are devastating to your credit report especially if you have little or no credit history already. You say you have good credit, but if you only carry one or two open credit accounts, that one incident can keep you from getting anything in the future, especially major purchases such as a car.
Just for clarification, every company that requires a payment for some kind of a service whether it be monthly, weekly, or annual will report negative account activity to the credit bureaus. Usually only installment loans and credit cards report good account activity though.