Employee victimisation

Hi yesterday i witnessed a employee being humiliated in front of us(customers)by her manager poor girl was only doing her job and we where waiting patiently for her to finish helping another customer until suddenly this woman her manager became hysterical and made fun of her in front of us just because the other customer didn't want to pay for a replacement card which the poor girl did let her know that she has to pay for it,anyway i asked the poor girl her name,she said Nthabiseng and her Manger is Thandi n told her that i will report what i had witnessed at the store,sadly she told me that its a an ongoing thing at shop ,she victimizes her especially her but not the other staff sadly she told me she cant leave her job cause it supported her and her two siblings because her parents passed, i felt so ashamed to be a manager and to see another manager be so cruel ,i dont think she has any leadership qualities she is old and should be the one mentoring the young individual so that she one day can be a loyal employee and a great asset to the company in the future.