TAKEN ADVANTAGE OF BY MAZDA BLOEMFONTEIN

good day I am a small business owner and was requested to carry out some work for Mazda Bloemfontein in February 2021. After the requested work was completed and invoiced, now Mazda Bloemfontein will not pay the invoice as per the job requested. Is this how they treat small businesses? It seems as if they take advantage of small businesses. All I want is my payment for what was requested and agreed upon.