Car battery problem

I bought a battery May 2025 at Hercules Pretoria, Pro Touch Batteries CC ***). Since last October 2025, having problems with the battery. They take me from pillar to post, saying my car has electric fault I took it to electricians but find no problem. I took my car back to this company. Salesman told me that next time when I come with same problem I need to tell their boss about this same problem.