Lending a friend money,and not getting it back

Last year ,I lent a friend alot of money ,he convinced me that he lost his wallet and needed money for certain payment,promising that he will return it after 3 month,he payed some of it then delayed it to the next year and now he tells me to forget about it till he can return it. Now there is a feeling of regret not only because of the money which ,I Lent in expectation of getting it back but also because the friendship got affected . Feeling that he is a liar made me think , I should've been mindful of the deception.As well as not having any compassion for him. What should be done right now according to Buddhism?.