My friend paid for their service and did not received the work.
They agreed for refund, but didn't do it.
When claimed went to the issuing bank, Assignmentexpert.com sent an email to the bank with "god knows who with email id does belongs to my friend" stated the work was given.

My friend pursued the case further, Assignmentexpert.com sent the below email.
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From: Contact at MAE <contact@myassignmentexpert.com>
Date: Sat, Oct 19, 2013
Subject: Regarding chargeback

Dear Sir
As you have decided to ignore our mail, "university" officials will be hearing from us soon.

On 18 October 2013 15:05,
Contact at MAE <contact@myassignmentexpert.com> wrote:

Dear Sir
This email is in response to the chargeback that you levied on us recently. Read this mail in its entirety to avoid any unintended consequences later on.

We have decided to contest the chargeback using all the means available to us.

1. Through our network of agents, we have been able to locate your University.

2. As you violated our policy on chargebacks, we are hereby levying a fine of 1,980 USD (non-negotiable) which must be submitted to our account within 24 hours.

3. If we do not receive a response from you within 24 hours, we will send a mail to your current University to inform them that you seek help from websites to complete your assignments. We have ample evidence to support our claim.

We are forced to take this action as you levied a chargeback on us.
//

I deleted the name of recipient and the university.
This is extortion!!!