Bad after sales and no support on their products

I bought two 7.2kwh Lithium ion batteries from this outfit on 4 January 2022I only set them up on 5 January to find that the Battery management system doesn’t work. They BMS says they are only 5kwh, the BMS doesn’t show voltage and charge capacity. I reported this to them through their WhatsApp and email since 6 January 2022 and to date no technical person has responded and sought to address the challenge. I have requested for refund or replacement and no response on any request. I requested a manual for the batteries and nothing provided.