Pay in 3 payment issues

I had a terrible experience with the new pay in 3 system. I had already paid my first instalments and in the current month, my second instalments were due. I tried to manually pay the second instalments but the app made me pay the first instalments again whereby one payment was 3x what I needed to pay in the current month. So already Payflex had more than what I needed to pay this month and excess which had to be refunded to me. Furthermore, I got an email that my instalments bounced while they still had my excess. I made the payment on the 24th in the ams and I sent an email to support the same day, no response was received. On the 25th the only response I got was steps on how to make a payment which I was so confused because that was not part of the query I made I went into detail in my email even wrote down the amounts, order date, order reference etc. I was very disappointed in the support service I got. I tried calling the Payflex support number during the day and it kept on saying there are no consultants in the que, mind you this was 2pm in the afternoon tried again at 3pm same problem. I am disappointed as I’ve been with Payflex for over 4 years and I’ve never had any issues. The new pay in 3 was a nice invention but it looks like it still has some teething issues not yet addressed. Please address these as it looks like I have to be out of pocket and get no support when I really need it. On top of that get warning emails that my account is overdrawn.