Yes, you can easily lose your coins by using a wrong wallet. there are a lot of phishing wallets out there, be careful to use a wallet and gather details or do some research before you choose the one.
To avoid that, I recommend to just using some well-known exchange sites and some trusted web wallet like MEW,Waveswallet,Neotracker. Surely an app wallet is more secure, because you're the only one having it's file. Once got hacked by anyone, your coins / tokens will disappear forever.
Even some well-known exchange sites is a huge risk if you leave a lot of coins there. They can all be hacked and usually it is only a question of time until it happens.