Best plug in to use for selling services? here is my scenario

Hi guys, i need some guidance!

FYI I am new to WP and was able to install it. I also installed WooCommerce but it doesnt meet my needs. My pricing is more complex or I may not be using it right. I asking help in choosing the correct plugin or instructions on how to use WC properly.

First of, I am selling a service not a product. I refurbish items at my shop, to reach more customers I want to offer my service to anyone in the US. Customers will ship me their items, I will refurbish them and ship them back. Because I don’t want them to abandon at checkout, I will to offer free shipping. I want to structure my pricing so that it cost more if they get 4 items or less refurbished (to cover part of shipping). After they’ve reached this threshold, pricing is per additional item. Here is a twist, if they are shipping me too many items, shipping cost will go up so I need to charge an additional fee to help cover.

My price needs to be structured in the following way:
Min item of 4 at X price
Additional service at Z rate each item
if total items reaches Y figure, charge additional fee

Example 1
Total service of 10 items
First 4 at X price
6 remaining at Z rate each
1X + 6(Z)= Total

Example 2
Total service of 30 items
First 4 at $X price
26 remaining at $Z each
Additional fee of $Y after 15
1X + 6(Z) + 1Y = Total

Example 3 using actual figures

Total service of 20
First 4 at $10 price (total)
16 remaining at $2 each
Additional fee of $5 after 15
$10+16($2)+$5= Total
$10+$32+$5=$47

Hope someone can nudge me in the right direction!