SignCraft Africa , abuse on small businesses in Kzn

I am a female entrepreneur that works with fibreglass . I was approached by Sign Craft Africa to make privacy screens for which signage is app**** to and fitted to the Standard Bank atms . I quoted them a price to which they agreed and sent me a PO with the quoted price on it . The order was for 10 , however i made 5 and stopped as me trying to get payment from them seemed to become impossible . They took the 5 completed products from my company and promised payment in 3 days . They came back to me saying they dont want to buy the agreed price but rather a price they seem fit, they have not been communicating with me and every time I try to get answers from them there is a run around . No one should ever do business with a company that does not have the slightest bit of honesty and integrity . They advertise they are throughout Africa and doing a starling job while they make small businesses like mine suffer , especially with covid and the unrest we experienced in Kzn . They have just gone quite on me but they are business as usual at their shop in La Mercy , is this how we treat black female entrepreneurs, who are trying to create employment and keep our company doors open .