You can click "Get Help From Upwork" button on the Help Center Page, select whether you are a client or a freelancer and the categories that best describe your issue. If the offered solution don't address your issue, click "No" and Submit Request. You'll see your support options that should include chat since you are Top Rated.
Due to the volume of users on the site, live chat isn't always available to everybody. I see you have already submitted a ticket about the duplicate bonus payment a client sent to you and we'll have one of our agents address it shortly.
Also, please refer to the latest message in this ticket for explanation of how Service Fee was calculated for the first payment.