How do the loisel's pay for the necklace replacements?

The Loisels pay for the replacement necklace by taking on significant debt. They borrow money from various lenders and spend the next ten years working tirelessly to repay the loans. This financial burden drastically changes their lives, leading them to live in poverty and struggle to make ends meet. Ultimately, they sacrifice their comfortable lifestyle for the sake of replacing the necklace.