I FEEL ********** BY CASH CONVERTERS BELLVILLE

Hi I feel I've been short changed I took an almost new 500gig Seagate portable Hard drive to cash converters Bellville and I was given R75 for it, I hardly ever used this hard drive and it was in immaculate condition, USB 3.0 , this is not right I saw similar hard drives at other cash converters for roughly R500, I feel this hard drive was at least worth R250, the one guy that helped us didn't let us get a word in edge ways, I'm a bit disappointed, there is definitely something wrong, I would appreciate it if somebody can assist in this matter