Hi an American citizen borrowed money from me in...

We would like to inform you that According to the Civil Transactions Law, Federal Law 10 of 1992 issuing the Evidence Act in Civil and Commercial Transactions, below articles state:
Article 35
1 - In non-commercial materials, if the disposal is more than 5000 AED or if it is of no value, the testimony of witnesses in proof of its existence or its expiry may not be valid unless there is an agreement or provision stipulating otherwise.
2 - The obligation is estimated considering its value at the time the disposal is issued without adding the attachments to the original.
3- If the lawsuit includes multiple requests arising from multiple sources, evidence may be attested by the testimony of witnesses in each application, the value of which does not exceed 5000 AED , even if these requests as a whole exceed that value, or if their origins are relations between the litigants themselves or behaviors of one nature.
4- The lesson is to prove partial fulfillment of the value of the original obligation.
Article 36
Evidence cannot be attested by witness testimony even if the value does not exceed 5000 AED in the following cases:
1- In what contradicts or exceeds what is included in the written evidence.
2- If what is required is the remainder or part of a right, it may only be proven in writing.
3- If one of the litigants in the lawsuit claims more than 5000 AED in value, then his request shall be changed to no more than this value.
Article 37
Evidence may be attested by the testimony of witnesses, as it should have been proven in writing in the following cases:
1- If there is a principle that is proven by writing, and the principle of proof of writing is considered every writing issued by the opponent and that would make the existence of the alleged behavior close to possibility.
2- If there is a physical or literary impediment to obtaining written evidence.
3- If the creditor loses his written support due to a foreigner who has no hand in it.
4- If the court decides, for good reasons, to allow evidence to testify.
5- If he challenged the written evidence that it contains what is prohibited by law or contrary to public order or public morals.
Therefore, if the debt is more than 5000 AED , then you can file a case and provide witnesses and documents to prove, and the court will estimate them.