How to pay invoice customer with vendors bill or vice versa in odoo 10? Or to cut the original invoice with the refunds invoice.

In odoo 10, there are customer/supplier payment that can do this job. But how this can be done in odoo 10?

For example:

Customer A is also my Vendors. I bought item X at 10 USD and he bought my item at 3$.

How to cut the 10$ with the 3$ bill and leave the invoice at 7$?