New York City’s Museum of Sex hasn’t paid any sales taxes for four years and is now facing an $82,192 tax lien from state tax authorities.

The problem stems from discounts that the museum offered to group coupon sites such as Groupon and Living Social, according to the New York Post. Those discounts could provide up to 50 percent off the admission charge.

Apparently the discount sites generated much of the business for the museum in recent years, and according to a spokesperson, they were expecting the sites to charge the sales tax once the vouchers were redeemed. However, other museums that use Groupon and Living Social aren’t facing tax liens.

On the other hand, the items for sale in the gift shop for most other museums are reportedly a lot different from the toys available at the Museum of Sex.

A spokesperson for the museum told the Post that it has paid off $17,000 on its tax debts and is making monthly payments on the remaining $65,000.