Incorrect. Unable to compete and inadequate customer support are the reasons.
Samsung used to have a big user base in China. But product offerings from local manufactures became much better. Design, software and quality wise, they suit the customers' needs better. Samsung's products are simply - "meh".
In terms of customer support, Samsung treated Chinese customers like second class citizen. E.g. during the faulty emmc and fire-catching battery fiasco, they refused to offer the same level of customer service as they did in the US and Europe.
When the first/second case of exploding battery surfaced, Samsung accused the owner putting his phone in a microwave to cause the battery to explode.
Also Samsung adopts some dirty marketing tricks which is well known in China. They have been fined in Taiwan before.
https://www.theguardian.com/technology/2013/oct/24/samsung-f...
All the factors combined, caused their market share to plummet.