Shopify eCommerce Store App Conflict Resolution

Running an online Shopify ecommerce store selling furniture.
Running Hyperspeed theme
Running 2 apps that control the cost of shipping
1- Estimated freight
2. Advanced shipping rules

Current issue seems that the Estimated freight app which I need on the product page so clients can enter their postcode and receive the cost of shipping based on the rules in Advanced shipping rules, is making the shopping cart crash in certain conditions, my developer has removed the estimated freight app to test if its the issue and it seems to be working fine and not crash when not installed but I do need it installed and need all to work smoothly.

The issue seems to be that once there either 2 of the same items any additional item wont load or disappear from the cart also can't add to the cart more than 3 different items

from m the research i've done issue is a Critical AJAX JavaScript conflict something that for a skilled developer should be a very easy fix, also with Hyper speed theme cart can only be set to Drawer or pop up it crashes if Pages option is chosen, also the Dynamic Payment button cannot be switched off don't think it's the issue but just saying bottom line I believe the AJAX JavaScript is the main issue and needs to be resolved on the script level