Instagram Hacking

Someone has gained access to my account and changed my password and account details. I have been blocked out so can not reset password. The person is using my account, posting and following people. I have reported this and it has not been resolved. My last communication was on Thursday asking me to detail my issue. I have done so and no response. Can someone from Instagram please urgently assist. I am reachable on my email. Regards. Lerato Makume