After buyer selects size and colour, they go back to default choice in the cart

Job ID: 34826968

Budget: $10 – $50 USD

I have a problem in our store, is that when buyers choose size and colours, when it goes to Cart it changes back to the default size and colour (the choice ranked first in the drop down).

We want the buyers to be forced to change (not able to continue without choosing) the colour and size, and when they change it they remain as changed, not change back to default.

Please check the product page:

https://classypetlife.com/en-gb/products/personalized-breathable-dog-harness

We are using shopify, the theme name is Debutify, we are not willing to change the theme. Please don't tell me to award the project untill you are 100% sure you can fix it