How to allow customers to select dishes after purchasing a package?

[Pims]

Hi everyone,

Website: https://www.bonapeticongelados.com/

2 weeks ago we have decided to offer packages on our food website.
It works as follow:
People decide which package they want to buy, they purchase it and then they have to select 10 dishes among all the dishes we offers on our website. 
My problem is that i have not found a way to allow people to get back to my store one they have purchased their package, to make their selection of dishes. So what we do is contacting them through Whatssap or calling them to know their selection which is very annoying and confusing for our customers. It should be easier.

I do not know if there is any application that allows to do that o any code?

I really hope that someone will be able to help us.

Thank you in advance for your help