Hello Pinki, the best way to develop your confidence level is to improve your thinking level. Just have belief in yourself and your skills and believe that you can do anything through the sheer will of you hard work. You need to have a vision what you wan to become in life, then only you will start working towards that and that will increase your confidence level. Don't be afraid of anything and do things which you don't like for increasing your confidence. For improving your language skills, you just need practice. Start speaking english with a couple of people at start and then more later, chose english language while talking to the customer care. Think in english in your mind. Use english on whatsapp rather than writing hindi in english.