One of the few states which paid their debt to the full was Haïti.
Under an agreement with Charles X, any claim on haïtian independence, properties or slaves were dropped by former french owners, if the Haïtian government would pay 30 millions Francs what is today equivalent of 17 bn euros, then close to 1 year of Haïti GNP (37 millions) and 15% of french budget.
Haïti did pay, from 1832 to 1883 for the capital, and until 1952 for the interest and subsequent loans.
The burden ot the debt hindered any development policy, but no haitian goverment chose to pronounce a default. Haïti is now one of the poorer state on Earth.
In France, slave trade was abolished in 1815 by Napoleon then Louis XVIII, slavery in 1848 by 2nd Repubilc.
6 millions Francs were immediately paid to owners as indemnisation for 250.000 slaves, plus every year for 20 years 5% interest Francs of a 120 millions Francs capital (i.e. 120 millions total amount, today equivalent of at least 50 bn euros).