(Kadamba Kanana Swami, 15 December, 2013, Soweto, South Africa, lecture)
If you commit vaiṣṇava-aparādha then you do not lose your pious credits from your devotional service. It still stays in your spiritual bank account but what happens is that your bank account gets frozen. Just like when you have a bank account and the government freezes your bank account and you cannot get the money. So when you commit vaiṣṇava-aparādha, your bank account of the spiritual credit gets frozen. Then you have to suffer for sometime and then when you get purified by the suffering then again you can get access to your spiritual bank account.
So, if you commit vaiṣṇava-aparādha, you suffer the reactions for sometime and then you carry on with all the benefit from all the chanting. So nothing can destroy the effect of chanting, not even vaiṣṇava-aparādha but it can freeze your bank account!