Alternative modes to pay

It seems odd that in modern society, debt can only seem to be paid by way of money.
No labor in exchange for debt taken off, no goods can be transferred at a sort of fixed values, children can't be exchanged (thankfully), or any of the sort. The concept of exchanging items of various values in lieu of paper money to absolve a debt issue seems ridiculous.
Why has this fallen out of fashion? Is there no means by which, say, people of impoverished areas that have no money because of the institutionalized means that rendered them penniless can absolve a debt? It goes further to say the debt at stark interest rates will never be completely repaid.
This is the state by which many countries of the global south live, seemingly & quite possibly forever indebted to the Western hemisphere even though the original debt may have already been repaid several times over. Even the extraction of their resources (though may be paid for, we all know that fair trade is hardly a thing in most cases) cannot pull them out of debt.
By what principle is it fair that countries that have been trodden all over, lived through violent experiences of colonialism / imperialism, and subject to indefinite struggles just to get by still owe money to their oppressors?
Clearly, the way debt is handled in society today can be measured as an injustice that has an atrocious historical narrative to explain its horizons. Unfortunately, it seems the primary method has been & is to enforce capitalist principles by way of militarized force or full punishment of the laws.

I guess what I'm asking / thinking about here is other ways in which "debt" can be remedied. It floors me knowing that while it seems that as students, many of us have large-scale debt to be confronted in the future (large-scale debt that is going to be even larger-scale plus interest), is miniscule compared to the amount of dollar debt our entire nation is in. This is where questions of how this is possible are appropriate. The answer? It is possible because of violations against human rights, against "property rights" of others, and unequal distribution of wealth / resources due to particular institutionalized circumstances.

Now, consider whether individual debt means much over the whole scale world debt. It seems that everyone is in debt to everyone, whether by dollar or by transitional justice mechanisms. Through the this sort of lens, we see that the debt crisis calls for a much more political answer, ignoring the concept of individual debt. (check out http://www.sharing.org/ a movement dedicated to sharing the world's resources for some hope / insight on alternative methods of fighting the global debt crisis)