[Bill] $40 for Service Call High-Speed Internet?

I got my bill this month and Comcast billed me $40 for a service call I had regarding problems with my Internet service. Why? Edit: I called Comcast and was told it's because I had inside work done and didn't have the protection plan. The "inside work" was replacing a splitter and that was because I was having Internet problems. Note the splitter didn't do anything, they just decided to replace it. That doesn't seem right to me at all.