All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His Slave and Messenger.
As for what you have done of licking clothes mistakenly does not invalidate your fasting. Rather, if something unintentionally enters your stomach, your fasting is not broken. Then, how about if the matter is just licking the clothes, let alone its being unintentional.
As for waiving the debt, it does not count except with words that indicate so, whether explicit or implicit along with an indication. The Kuwaiti Fiqh Encyclopedia reads: “Waiving the debt occurs by all the words that achieve what is meant by them, i.e. waiving the financial right of the creditor against the debtor, provided that the wording should have clear indication of the effect (waiving the right and the one whose debt is waived). This is done by every wording that indicates it explicitly or implicitly along with an indication.”
Accordingly, if a person intends in his heart to waive his right (debt) against a person without saying what indicates that, then letting that person off does not occur at all, and thus, he can take his debt if the debtor gives it to him.
Allaah Knows best.