Buffalo Logistics inflating Duty and Vat

I have 2 orders on its way with Buffalo Logistics via Temu order 1 - R477 invoiced customs R235? order 2 - R265 invoiced, customs R235? I have attempted to contact a manager at Buffalo Logistics since monday.... always busy, out of the office, or will call you back, as all the call centre agent advice is to speak to SARS. My issue is not the duty and VAT but rather how it is calculated. Product price R300 on sale R150 based on my calculation Buffalo is calculating based on R300 whereas SARS stipulates should be based on what you paid for the item