Dunno about Lazada or any other online shops, but be very careful when purchasing from gray market. i personally know someone who cheaped out on buying an iphone 4s and bought from a gray market shop in GH. Soon after she couldn't get a signal, receive text, etc. We speculated that the unit could have been stolen, and the original owner had it blocked. she couldn't bring it to the official Apple store since the unit was made in Korea(kelangan daw sa apple shop ng Korea dadalhin). In the end out of sheer frustration, she sold it for spare parts. 20k+ down the drain all because she wanted to save a few thousand pesos
Personally, i bought a Galaxy S2 from an official store; one month to go before the warranty expired, the WiFi suddenly wouldn't work(was about to sell it). i brought it back to the shop, found out that the mobo got fried. They replaced the board with no question...so i kinda got a new phone ^_^
i'm sure quite a few will disagree, and taga talaga yung mga "official" stores dito...but for me, if the item is a gadget, and it's worth upwards of 20-25k, i bite the bullet and buy from the official store -- me certain malas lang siguro ako when it comes to these things ^_^