supposedly it's sms for ringtones and wallpapers - but I have only seen one type 7990 number even that, no link to download the info from ... and there some other numbers ...
3/ sms is a lot - especially useless ones :(
I don't know how to deactivate it :( but I do only go to one Du shop. This is the one at Ibn Battuta. They seem to be the only shop that will sort your problems before you leave. If you have a complaint they will fill in the form and authorise the repayment of money as well. Good luck.
just received my bill and there are about 15 sms charges of Dhs 3/each to a 4 digit number as such 7990.
anyone know how to deactivate this 3rd party delivering sms which I do not know about and Du has been useless in guiding me how to unsubscribe.