Blocked account without any explanation

On Friday 6 April I sold something online. After receiving the proof of payment and confirming the money showing in my account, I assumed everything was well and I sent the goods. However, on Monday 8 April I discovered my bank account has been blocked. Apparently the transaction was flagged as ***** (which I only found out after making multiple calls to the call center). They required me to get an affidavit and to send that together with the proof of payment to the ***** department ********** ********** and ********** which I did.

Since then I have barely had a response from them. Today, after calling the ***** department call center again they told me they never received my documents (which I had sent more than once). The people there don't have any information on the actual case and I'm not allowed to talk to any of the investigators. So I re-sent my documents again, multiple times.

In the mean time I'm locked out of my account. I've been a customer for almost 20 years now, and this is how one get treated when you're the victim of ***** (which I assume I am, as no-one has told me why my account was blocked in the first place). I DESPERATELY need access to my account as I have funds in there which I need.

I have logged multiple complaints to no avail. The complaint reference numbers are ********** 070, ********** 197 and ********** 800.

I have emailed the ***** department multiple times and they simply don't respond.

This is completely unacceptable service. I need access to my account as soon as possible.