League of Legends has to be launched from Garena platform in several Asian regions, similar to games on Steam. Playing LoL becomes impossible if Garena bans you from their platform for purchasing Riot Points from, well, Garena's Shopee.
A League of Legends player took to Reddit to warn any other players who are stuck with Garena launcher that they might get banned from the platform if they purchase Riot Points from Garena's own online shop, Shopee. Technically, Shopee is more of a trading platform like eBay or Amazon, so you might start getting the idea what went wrong here.
Reddit user RenzuMame used to purchase Garena Shells, which are Garena's version of Riot Points from Shopee and everything was fine for a while. The player was then abruptly banned from Garena, and effectively from League of Legends, since they couldn't launch the game without Garena's launcher.
When RenzuMame contacted Garena's support, they told Renzu that their Shell purchase from October 2017 was "fraudulent". Apparently, it was the code that Renzu added to their account to get a certain amount of currency that turned out to be fraudulent or was purchased in a fraudulent way.
The latter might be closer to the truth as Garena asked for a proof of purchase next and when Renzu provided them with a screenshot of the transaction, they asked for credit card details. Renzu couldn't provide more information due to expired notifications, at which point Garena closed the case, tagged it as "resolved" and told Renzu they would keep working on it.
Fast forward two weeks, at least, and Renzu is posting this thread on Reddit, still without any progress. One of the commenters made a point that Garena "sounds like a horrible company", citing bitcoin mining, bad esports organisation and professional team mishandling as the reasons for this description.
Another user replied to this comment by pointing out the fact that both Riot Games and Garena are owned by Tencent and keeping things in-house is likely the reason why this partnership isn't breaking apart.