DHL Express - poor customer service

DHL - Query case - *** - ***8 AWB *** Case Number: ***8 I had purchased items from the UK - however was billed incorrectly for the import duties, i however only realized this 1 day after i paid online. I should be refunded as agreed by DHL representative (Leni Olivier) I was then told to fill forms in and supply information to DHL, that DHL has all the shipping information already, yet they asking me to supply it ( its all online, as they provided it to me ) These are customs forms where I have no idea how to fill in as many logistics jargon. DHL was paid for their service and was done incorrectly, now im blatantly told by Leni Olivier the case is closed as I cant fill in this form. I paid for DHL to clear this, they did not do their job correctly now im expected to fill in Logistics jargon/customs forms that i have no idea how to do correctly.