Question

an instance where sellers should work to keep relationships with consumers is when they feel that the product ???

Answer 1

it's when they feel that the product Value goes beyond its function.
When Value goes beyond its function, there is an idenitfiable benefit that customers could directly get from the product.
Which means, the only thing that sellers could rely on to keep selling the product is the customers' loyalty.

Answer 2

Whenever the product value goes beyond its function it becomes an immediate call for sellers to keep the relationship with the customers strong and intact. A strong relationship between sellers and customers at this time is a must to save the sales of the product.