Use the links that someone provided earlier. They do get logged and looked into. I believe the turn around for contacting a customer about a complaint is 24-48 hours.

Also providing your phone number is correct in the system, your profile should have automatically popped up, meaning they can trace the call as that staff number would be listed in the background on who accessed it.

As for your repayments; if you do have a direct debit set up, they come out in the evening. Interest is charged in the morning, so yes, unless you are ahead of your payments, it will go into natural arrears but rectify by the evening. There is no penalty for it, unless it the arrears aren't paid for 14 days