Refine the modules in bitrix

www.idmkniga.ru Website
There is a test version. git is not.

Tasks
1) Finalization of the basket functionality: when opening the basket, it is necessary to recalculate based on the amount of goods in warehouses and the current price of the goods (in 2 versions of the basket - for individuals and wholesale buyers).
2) To correct errors that occur during the update (more details are ready to report in the TK)
3) Optimize delays and correct errors in the checkout section when choosing PVZ boxberry and SDEK
4) Correct the error with inaccurate display of the balance on the goods (more details are ready to report in the TK)
5) Fix the error with the display of discounts in the version of the site for wholesale buyers (price list for the mobile version of the site)