Two drop down on referenced collection, cant submit data to main collection.

hi,
I have created two drop down filters that use items from a referenced collection. This works fine. Only problem is now the submitted data wont show up on repeaters. There is an error on submit. Do I need to update the main database using the below code?

const dropdown = e.target;
const membershipId = dropdown.options[dropdown.selectedIndex].value;
wixData.update(‘members’, { _id: memberId, membership: membershipId })
.catch(err => {
let errorMsg = err;
});