This is simply the way it works at LH. They send it off and someone in the back office will issue the refund. But, to be clear, you can calculate this yourself. You will be refunded the taxes. Taxes do not include carrier surcharges. So, figure out the breakdown of that $750 and total up the taxes (incl. government-imposed fees) and that is what you will get back. If you have trouble breaking down the $750, LH can provide that breakdown over the phone.

You will lose the base fare + carrier surcharges.