Reference: Fataawa Noor ‘alad-Darb – Question No.6293, Page 122, Volume 12
Question: Does repentance expiate [the sin of dealing with] ribaa?
Response: Repentance expiates everything, and wipes away [the sin of] what has [since] passed – [whether it be] ribaa or other than it. However, regarding ribaa, Allaah (Ta’aala) says:
[So] if a person repents from dealing with ribaa – with the condition that he has not yet been paid, then he is only permitted to take back his equity capital. For example, a man [A] gave someone [B] 1,000 riyals, on the basis that he [B] pays back 1,200 riyals after a year…and this [here] is ribaa.
So if Allaah blesses him [A] and [as a result] he repents [from having dealt with ribaa], then he must only take back 1,000 riyals from his companion [B]; and this is based upon His (Ta’aala) saying: