rave are awesome but did you know they ripping people off?

I was in rave festival music witch is awesome but the problem start when they did not want to take cash or debit or creadit cards at lines for drinks or food, you have buy credit with you prefernt choice and loaded to your RFID CHIP
if for any reason you dont have enoght to purchase what you need you prety much loss you money or you have to pay 5$ refound fee
For readon this is a systematicaly a robery!
Lets say if the drink cost 9$ and if you have 8.90$
You cant buy it and if you want to get a refund you have to pay 5$ fee for it so 8.90$ - 5$ refound fee ypu will get back 4.90$!!!!
How in the word this not a robbery.