Roto-Rooter Services review: Complaint

I have a bathroom shower/tub combination which is completely enclosed by glass sliding doors. When you want to use the "shower", you have to pull up a type of Knob so that it can activate the shower to turn on. Recently I pulled the Knob to start the shower and the Knob fell off. Thinking it had broken off, I could not take a shower until I could have the "knob" fixed. I called Roto-Rooter located in East /bay, Calif to have them come to my house to fix "the knob". The service person for Roto Rooter came today and when he looked at the "broken Knob", he said, that it was not broken but had only become "unscrewed" and put the Knob back on the post it sets on. I admit this was my mistake and I am willing to pay a reasonable amount for his wasted time but when he charged me $117.00... I was shocked! He wasn't there more than 15 minutes! I did as he asked and put the "$117.00 on my credit card. The more I thought about it, the more I felt like I was ripped off and I am wondering it there is some way I could recover some of that charge of $117.00. I would appreciate your response. Mary Rodrigues [protected]