Today I have sent a little Ethereum to my address but it instantly transferred to another address. Later, I tried again sending 0.002 ETH and the same. It also transferred that same address instantly.
How to get solve this?
I have seen these case quite number of times, and I think it only occurs when you have a spam software already on your system that is changing the address for you, first you need to take more precaution, there is nothing you can do about the ones you have transferred already, as they are already lost and gone but you can further prevent it.
I would advise that you first format your system and get a very strong anti-spamming tool, then change your password to a very strong one, never use a weak password as they are easy to guess, for your mail, change all the passwords too, use 2 authenticated password as I see that we have lots of some software too that tries hijacking my crypto mail several times.