Interstate All Battery Center

Have used Interstate 3 years in a row now. My son called me yesterday a.m @ 9:30 a.m. His car battery was dead. Having called them before and ordered a mobile install for a refurbished battery gave them his address and Interstate said they had it handled. Long story short they never made it. They said they couldn't make it but would be out first thing. Oh they made it out o.k. and swapped it out took the core and charged me approximately 300 % more than the previous two years. Well aware of the fact that the cost of car batteries has gone up. But by nearly 300% I know not. Could have bought a brand new battery drove down installed it myself for less money. Won't be using Interstate anymore to say the least. Would really like to find out what has gone wrong with a company that used to be fantastic.