The customer service with flipkart is not good because they do not exchange their product easily.
The product quality is usually okay but not always my two friends bought redmi note 4 both from flipkart and one’s phone is okay but the other one’s is not.
Apart from all this the worst thing is the delivery time they usually take a lot of time in delivering their products whenever I think of buying from flipkart but after thinking I dont buy because they take long delivery time.
The app of flipkart has an update after few weeks and it drains my data pack. The search option shows many phones with unupdated price and that irritates me a lot.
In terms of reliability the app is not highly reliable but it is reliable. Ordering from flipkart sometimes is risky but it is still reliable.