Not all oil pumps in the country are fraud. Some of them are factory or company owned so they can be trusted. About metro, makro and hyperstar. Metro makro are fine but hyperstar is suspicious, I have had bad experiences from them in case of other things and no longer visit them.
The other oil than caltex that I use is valvoline and I go to filter house, is it reliable enough.
The shops offering oil on discount are always suspicious.
Once I had spare time and scrolled the net the oil recycling machines are as low as 500,000 rs. so cheap to buy such machines