One of the late Sheikh Saud bin Mohammed Al-Thani’s final purchases is catching up with him, as members of Qatar’s ruling family are now being sued for some $7.5 million that the collector’s estate still owes for a set of rare stamps he won at auction before his death.

Known as the “British Guiana collection,” the stamps, from the estate of John E. du Pont, were offered by David Feldman Stamp Auctions in June. Though the price may seem extravagant, it was not even the most expensive stamp auction of that month: a 19th-century one-cent magenta, also from the du Pont estate by way of British colonial Guiana, fetched an astronomical $9.5 from an anonymous buyer at Sotheby’s New York, smashing the record for a single stamp.

As part of the terms of the sale to Sheikh Saud, the Swiss auctioneer agreed to accept monthly installments in lieu of a lump sum payment, but Feldman has now filed a suit in Manhattan federal court claiming to have only received $872,000 in payments before the sheikh died in November.

In addition to targeting Sheikh Saud’s estate, the suit also names Sotheby’s Financial Services, which had given the Qatari patriarch a pawn shop-like loan: Sheikh Saud received $30 million, while Sotheby’s got to hold onto $83 million-worth of his valuable art objects and collectibles as collateral.

“The sheikh’s personal art collection is currently being inventoried and assessed. Once this process has been completed, as well as the sale of certain art and jewelry pieces, all of his debts will be paid in full, with any shortages to be guaranteed by the royal family of Qatar,” art consultant Malcolm Harris, who represents Sheikh Saud’s family, assured the New York Post. He claims that his clients were “owed a great deal of money at the time of his death that his family may never see again.”

In addition to various personal debts, Sheikh Saud also owed large amounts of money related to other purchases of fine art, jewelry, and furs. Presumably, the proceeds from the $24 million sale of the late sheikh’s watch, sold to help satisfy some of those debts, will help—if only a little bit.