I am a Latvian citizen (european union) , I was flying in transit from honk kong to london, and when I was flying before (last year and one time in this year ) I made some sky duty free shoping with my bank card total it was ~ 20 times because I was flying in bankgkok and honk kong and buying there some goods to sell in UK and Latvia: first time I was flying in June and last time when I was flying now from honk kong,I bought dutty free  with te same card, I didn't check my card balance for this time, just giving it in airplane, with that hope so sometimes I will pay to my UK bank . Now Airiline company emirates ask money from me for duty free shoping for all this time , also 3 times I was giving my debit card they shouldn't accept it but they accept it)
Value is 17000$ ,  police made for me 96 h visa, after visa was expired  police told so I need to wait an answer from public prosecution, I was at police again they told me so I am not arrested, and I can do what I want. 
On 15.04.2012 I have been to police station at airport they didt told me anything, just tell me so I need to wait ,  My 96 h visa is expired from Wednesday 11.04.2012
Next time when I was at police they told so they still not get answer from public prosecution
All the time police was asked for money but I told while I am staying here I can't pay.
Also I was buying airline ticket from some suspected person for cheap price, when I was at emirates office and asked about total amount they told me : 17000$ for sky shoping and 18000$ for tickets because company didn't receive a money for flight. ( that time when I was buying ticket from that person I didn't know about that so he is making tickets on others person card) 
My passport also is takken off and is in police station.
So : I was flying on suspected tickets since June last year, and 20 times I bought dutty free with my bank card, also this time when I was flying from honk kong to dubai I bought few goods, if there is no money on the card why they giving me that goods?

How you think in this case can they put me  in jail for fraud or just for unpaid? If for fraud so for how long time? What is better to told them if they ask: I know about that so my card is without money or to tell so I don't check my card for all the time?
When I am in court, its better for me to tell yes I am guilty or to tell not guilty? Because in other country if you agree so you are guilty they give you lower jail sentence, I don't know work this or not in this country.
I understand to don't sign any documents what I can't read or don't understand. On first day police give me some document to sign, I didn't sign it because it was on arabian language, I told I don't understand and I will not sign it.

Are they giving free lawyer at court? I read in dubai news so in court are aviliable free lawyers to poor defendants, its true?
And in my case : I was in tranzit not in this country, it is some plus for my situation? Or its don't change everything in my case? 
Local arab lawyer told me for this case they can put me in jail for 1-2 years, and if I answer I am not guilty they can put me in jail for 3 months just to check me in all the world. 
About tickets I told to emirati airlines so I was paying by cash to some person and I don't know how that person bought that tickets . Also I gave to emirati airline officer that person mobile phone number but I don't know that person is still on this phone or not.

I hope u can give me some helpful advice to run out this case.