Either the customer is a cheap-skate (hires hacks) or they were really taken by the previous service co. Four pumps in 2 mos does sound kinda strange though...
Regardless... take that pic and show it to the customer... and explain. You may have a customer for life... as well as referrals.
Galatians 2:20-21; Colossians 1: 21-22 & 26-27; 3:1-4; Romans Ch's 5-6-7-8
2 Chronicles 7:14
Quality work at a fair price with excellent customer service.