Does anyone know what we should do about this?

We've been erroneously charged every month for a very long time. We opened a case about this over 10 months ago and this is still open now as seller support have been trying to solve it ever since but have not been able to.

Some of the erroneous charges have been reimbursed to us from time to time, but the root cause of why they are still being charged each month has still not been successfully fixed. We are now owed reimbursements again.

I posted this on the forums here over 10 months ago and a moderator regularly updated us about this for the first 8 months or so, he also had a dedicated seller support rep assigned to the case, who was on the case for around 5 months and who I also spoke to on the phone.

But now for the past 2 months the moderator has not replied to anything and then last week the assigned seller support rep said they were leaving (not sure if leaving Amazon or just the case) and said another seller support rep would be in touch within 48 - 72 hours. It's now over a week and I've heard nothing despite sending 2 reminders.

I have spent upwards of 100 hours on this so far, and in 6 weeks it will be a year since the case was opened.

As seller support and the moderator have not been able to properly resolve this, does anyone know how this can be escalated beyond them, to someone who is able and willing to get this fixed?