Zivame — I'm complaining about my Zivame account which is being used by someone else

I received a mail stating that my order is confirmed, however, I didn't place any order. So, I tried to login and check what has actually happened. I saw that someone has placed an order using my account and z coins to some other address. Also, they changed my registered number by replacing 1 digit of it. I tried to contact customer service, they behaved normally saying that we'll cancel this order. However, I am not satisfied with the solution provided by them. This is privacy breach from their end and some one has tried to use my personal property which is not acceptable. I want strong action against this.