I need help getting connected with amazon and others. and I need help with billing.

We go through Shopify. We need help hooking up to some different channels. Plus we took a free 30 day trial offer with Sellbright app and all of a sudden I am getting charged for something about every 2 weeks and am I am wondering about the $200.00 charge. Should I shut that down what is it for. So we need some technical help with getting on some different channels. And need help with the billing on Sellbright.