Defective Product

Guys, it seems like shopping at this online outlet is lottery. I bought a Lenovo laptop for about 10K in the 1st week of June 2020 and the item was delivered in two weeks time and I was very pleased with that considering we were in lockdown level 5. To my short happiness, the laptop was not working it had a hardware problem because once I switched it on it keeps on restarting itself. I logged email for return and they picked it up on the 26 June 2020. So today is the 02 September I only hear after numerous emails I have sent that the distributor that the bought from claims that I have installed a defective ram in a laptop. How could I open a new laptop and install a ram? To cut story short I’ll advice if possible use other online shops and I avoid this guys cz you might be unfortunate like me and couple of others. Thank you South Africa