TEN days NO feedback

I have sent a query to *** and *** TEN days ago already to ask for help / assistance on my account:

"I paid the full amount outstanding and would like to know if I can change my payment date or plan so I can pay my normal monthly installment again from 25 August and not 25 July?"

It is now the 26th of July and my installment was due yesterday and now I can't make any changes as it is too late for July, thanks to the fact that it is 10 days since my query and I am STILL waiting for feedback.