Possibly new Taxi scam?

Posting this to understand if this is a new or an old scam and to make everybody aware of such scams in Mumbai. I took a train to CST recently and had to get somewhere 2kms away from the station. I hailed a taxi and the driver said it would be around 150. Firstly Idk much about the fares these drivers charge or if they do use meter etc. But I sat in their taxi and one or two minutes away from the destination, he handed me 350rs saying ‘Madam ye 350 rakhlo aur mujhe aap 500 dena’. First I felt a bit weird but I didn’t think much of it. Then once we reached the destination I handed him the 500rs note. He took the note, quickly hid it and within a second he flashed a 100rs note saying ‘madam aapko 500 ki note deni hai’; I was like ‘vohi toh di aapko’; He said nahi etc. And then I understood what was going on. I raised my voice and said ‘ye sab mat karo passengers ke saath etc’ and he understood I won’t be giving in cause all I had was 500rs notes and a few change notes of 20. So I was dead sure he is bluffing. Once I raised my voice he changed his tone and said ‘nahi maam mujhe laga aapko mene 100 kam diye islie pucha’. I was furious and just left from there and regretted not having noted down his taxi number. Also, i ignored a major thing that while on the way to the destination, he stopped by another taxi waved his hand and got some change from the other taxi driver — possibly the same 350 he gave to me. I was literally dumbfounded by this entire thing.