50-15=35€ no change returning at Lyca Mobile store near Chateau Landon in Paris

I was walking near the East Train Station and bought a small mp3 player like the runner type using for only 15€. But the clerk just took 50€ notes and he did not return any money back. And I complained in English and he just fixed the price tag on the packet from 15 to 10 and showed me the 10€ note and taunted me that I paid only 10€ instead. So, I lost 35€ missing. Normally haggling won't work in this way but the clerk said such a strange cheaper price making up as if for the crime building in the location. I could grab the 10€ and bring the mp3 player with me and if the cops see only such video parts from the surveillance camera, the clerk would claim me as a robber instead.

Anyway, the clerk could make 1/3 price bargain for unknown reason and it was filmed by the surveillance camera at the store. So, that could be exploited by the local mobs if they want the cheating merchants taking out in Paris. You can see the pen the clerk is holding as the situation.