Still owed them money

I took out these micro loans last year April, changed bank accounts and some of the debit orders did not go through. They were paid eventually, after that they phoned that there was still an amount outstanding, that was paid, went threw my bank statements and another amount went off without my knowledge, left it there as it was to much trouble, now this month the same is happening, and now there is this sms that if I don't pay there will be legal action, so watch out people. And they should not ask me to take this complaint off again, not going to happen.