Sun Lab sun screen

Dis-Chem sell a sun screen lation called Sun Lab. It states SPF 50+ but when I tried it I got burnt and do not believe it is more than SPF 15. It is endorsed by CANSA but they admit they rely on test reports from laboratories to verify the products. I asked Dis-Chem three weeks ago to send me the Sun Lab test certificates and they have yet to send anything to me which raises my doubts. I sent the complaint to The Star as well who published it.