New customer charged for tech visit

Hello, good morning, evening, whatever it may be for you lol! About a month ago I switched to Comcast and needed a coaxial outlet installed but was not aware I would be charged $100 for the technician visit! Its completely understandable but I was totally under the impression it was complimentary. I am upset and behind on money because of this. Please help me dispute this and receive a credit reimbursal for this.