Failed to deliver my package

I’ve ordered clothes from SHEIN on the 24th December, The last update I have was on the 5th January since then no communication from buffalo logistics, I started enquiring, that’s when they said my parcel has been marked lost , I demanded my refund, they send a refund form which I filled and emailed back to *** but no response from her even today , I called now they saying they are investigating they don’t know anything about refund, the Matt is under investigation, I lost my R622 and the levies or R100 something because of this company