Ocean Basket refuses to help!!

I worked for the company more than 3 years and started as a waiter and worked myself up to a Manager. A few years ago, I asked for a Certificate of Service and until today none whatsoever. I was communicating with someone over Facebook on their account. They returned a single call at 5 am in the morning (USA time) and every time I phone back or send a message there is no one in the office with no response on their end. The Head Office of this big corporation does not want to give me a certificate of service because I wasn't working for them, according to Ocean Basket. When I was working for this company, the owner of the shops son at Ocean Basket in Bela Bela is in the wind now so I have no proof that I worked for them during that time period. I am currently looking for work in the States and need a referral. The regional manager, Manny, was the manager over my shop. I communicated with him daily but Ocean Basket will not investigate to see that I was a manager at that location. Can somebody please contact me?