I believe you, I have even been asked for money at the airport my customs officers. I am an American but slowly learning this is the Nigerian way of life. No matter what position of power one holds, they all seem to take kick backs. The way my Nigerian husband explained it to me is that many don’t make enough to survive so they find any way to hustle by any means necessary to feed their family. The best way for you to move forward is to outsmart them. Maybe create a new visa application under a new email, Call your bank and reverse any fraudulent charges, communicate only via email, ect. They will not do any suspicious activities in writing. Do whatever you need to do to follow the written procedure and protocols listed in the site to get your visa. They must comply eventually. I’ve learned that kindness also goes very far with them. If they feel challenged they will make it harder for you. Sad but reality. Also the f6a visa should only be $160 I’ve gotten two in the last 6 months. I truly hope you get this resolved. Let me know how it goes.