Why...

...am I so forgetful? I opened a bank account a few weeks ago. I love the credit union I have always used, but it's in Salt Lake and I wanted to be able to access my money without making a special trip. When I opened the account, I also set up an online account with a username and password and created a PIN for my debit card. Fast forward a week.
I got my debit card in the mail, and decided I would also see if the online account works and if my PIN is somewhere online. Unfortunately, I somehow managed to forget my username, password, and PIN. However, I have a couple of base passwords, so I thought I would be OK. I tried several things, and then suddenly remembered what my password was. By then, however, my password had been disabled "for my security." OK, great. So I click on "My password has been disabled." The first thing it asks is for my PIN.
I don't know my PIN, so I guess. And guess again, and again, and so forth until I'm fairly certain that whatever I chose was completely random, and there was no good reason for my choice. It was definitely not something I remember. There is a link that says "I do not know my PIN", which I click. It takes me to a screen that says I should call a number and get help from a person.
So, I called the number. It instructs me to enter my account number, which I do. Next, it tells me to enter my PIN. I am stuck in a vicious cycle of non-PIN knowing.