I signed up during Ramadan, and got 50% off. But there was no code to enter. I rang Aramex and asked them for the code to get this discount and they said there was no code and that it would only debit $17.50 from my card even though it was indicating that it was going to take $35 (which by the way was the case).

I have just looked at the Shop&Ship section on Aramex and I notice the 50% saving is no longer mentioned. I know this doesn't help you, but in the event no one answers with a code, this may explain why.