Which will be better Cardiff metropolitan university or guglielmo Marconi university which is offered in westford school of management and I want to work in Dubai after completing it.

I can't imagine how either of these unaccredited MBAs would be helpful. What is your goal?

I have budget of 40,000 aed and with this budget I would get only unaccredited mbas.Actually I want to specialize in marketing.

And what will be best to do if I want to get good job in marketing:-
1.Online pg diploma in marketing from cim?
2.Online mba from unccredited UK or usa university.(unccredited because fees would be less)
3.Or regular pg diploma from any unccredited college?

I don't think one answer fits all applicants in this situation. I think a programme in marketing sounds better than an MBA for you, but you should get advice based on your goals. In particular, the CIM Postgraduate Diploma in Marketing is just as hood as a masters degree to people to are familiar with it. It's easy to top up to an MA or MSc.