Answer: creeping featurism
Explanation: Creeping featurism is a slang used for the term feature creep. It refers to the problem faced by the consumers due to continuous addition of features in an existing product. These addition make the product more complex and hard to use for the users.
In the given case, some customers of mobile phone have a belief that the new features added to the phones have made it complex and less reliable.
Thus, we can conclude that the given case is an example of creeping featurism.