There are three rounds of Interview.
1. English Test ( Grammer Test, 2 Letter writing, 1 Typing test )
2. HR Round
3. Operations Round (Final Round)
Questions are easy, the main test is to write the letter, which is basically replied to the customer. They go through these letters and find out how good you are in responding to critical situations. They judge based upon your writing skills, they also check grammatical errors, also the way you are handling things, Topics are given is a bit tricky, you need to thoroughly understand the overall context and reply back in a very professional manner.
Other things in the English test are easy. For HR and Operations Round, just be who you are and be confident, You will get the job easily. :)