UK LLC importing to USA fulfillment center and selling to customers globally

[D2Cbrands]

Hi, 

We are a physical goods e-commerce registered in the UK, sourcing and producing goods in China. We are looking to send a large stock to a fulfillment center in the US. 
We are looking for a service provider to take care of: 
a) Registering sales ID, accounting and reporting, 
b) Customs broker in the US

Please share your experience with similar tasks and suggest your recommendations. 

Thanks!