Hiding flaws and selling tyre with plug in as permanent fix

I bought a Merida bike from Bikemarket.co.za online for R29330. I dealt with a salesperson called Gavin at the Sandton branch(16 Dartfield Road, Kramerville)

1. The invoice I got did not give the discounted price even though I was EFTing the full amount. They tried to make me pay an extra: R750 2. Gavin ensured me the bike was checked and ready-to-ride - however failed to inform me that the bike had a catastrophic tyre failure previously - a massive hole they fixed with a mtb plug. 3. After noticing the plug after my 3rd ride on the bike and that it was not holding air - I requested Bikemarket to take corrective action and said I was disappointed. Gavin from bikemarket responded by saying he noted my disappointment but putting a plug in the tread (a known temporary fix) was acceptable to bikemarket policy and they never attempted to fix the situation.

They should not be seling products with defects (trying to cheat customers by not putting on a new R800 tyre. Just to save R800 on a R30k bike.

My recommendation would be to avoid bikemarket.co.za and rather buy from a reputable second hand seller on bikehub.co.za or buy the bike new.