That is awfully quick for EY to respond Fractionlord, considering applications aren't even closed yet? Only reason of this I can think of is that they have already filled up their AC.
In regards to phone interview:
1) well done in progressing
2) Make sure you are aware of a recent news item that can be applied to the services BDO offers
3) Don't prepare word for word answers, it is easy for the recruiter to pick up when you are repeating pre prepared responses.
4) Have your resume and the responses you gave for online application in front of you.
5) Research the firm throughly and also have an understanding of the area under which you wish to work
6) And importantly, although not essential but proves to be an advantage, ask questions as this shows that you are keen to learn and progress in the business
The rest is just basics, such as answer the phone in a formal manner and if you don't understand a question ask them to repeat it rather than trying to wing it, it is alright if you have to take a minute to come up with a response.
Lastly don't be nervous and be confident, the recruiters are judging you on your voice (Since they can't see you!!) so be clear and precise.
Best of luck