Non-competition clause or agreement in employment contracts

Hello there,

I was working for a company in Jebel Ali Free Zone since 2011 as a senior sales manager. I was asked to resign due to the company not performing well. I resigned.

Now, after 3 months I have a job offer in another Jebel Ali free zone company. I had signed a standard JAFZA non compete agreement in 2011.

I have told my former employer through emails where I am joining and I have received no objection from them verbally and a firm no objection through SMS from the signatory authority of the company.

They are dodging giving the letter. Will it be a problem for me in the future?