Payjustnow debits twice per month very bad

People be aware that Payjustnow is not good , they debited my account for two payments at once and they didn't find the second payment and I have a proof of this in my statement, they didn't find the second payment they were trying to deduct in one month now they busy charging me for late payments, I have sent them an email they not responding , I'm not happy and I will tell everyone I know to stop using Payjustnow