there you have it, your reference to the word "borrowed" presuppose the existence of a simple loan, and your allegations for estafa is doomed.

electronic mails or emails are now admissible in evidence in courts under certain qualifications. but what you have on hand is evidence of simple loan not estafa. in which case, if the amount involved is substantial, you are advised to seek a local lawyer to assist you in filing a simple case for sum of money and damages. Legal fees here are quite expensive, prepare with your deep wallet.