Williams Septic Service

I have called twice since having our septic pumped, both times I was told I would receive a call back to answer my question of a possible overcharge. We were charged 100 dollars more than our neighbor...we have less bedrooms and bathrooms than our neighbor. We both had our tanks cleaned 5 years ago....the truck was able to pull closer to our tanks than the neighbor's, and we both have the same size tanks, same number of persons living in the house. I wanted to know why we were charged more...
We will no longer use Williams nor will we recommend them