Bank charges

I am very disappointed with Payflex. I have been unable to get hold of them as the phones are not going through. I took out an agreement to pay within 3 months, and my next installment is due on the 20th of April. However, they have been checking my account to see if there are funds every time, and this is resulting in additional charges from my bank. Payflex is not good at all, and I would not advise anyone to use them. Terrible service.