I am assuming the context is a shop or purchase of some kind? This being the case, it just literally means 'it was neither returned (or possibly traded in, depending on the context) or exchanged'.
During the sales period (where you can buy goods with a big discount) shops usually specify that "les articles en soldes ne sont ni repris ni échangés".
The French law states that, for articles sold off at sale price, the shop owners are not forced to abide to the usual laws regarding goods that you can return to a shop if you are not satisfied; the sales period is fixed by the French government and the relevant laws are very strict.