Last updates to my case :

-A3 credited me the miles of the rebooked flight. A3 told me that asked info from ET but they never replied so after almost 2 weeks they credited the miles according to the original ticket.

- I also did the route ATH-LCA-LHR-ATH last Saturday which secured my A3G status for another 12 months.

- I have no reply from ET regarding my claim to get the 600EUR compensation. I hope they won't rip me off for the 6:30 hours delay I had in the first leg of my trip

I would like to thank again the forum for hosting and each of you replied to this thread for helping me sorting this out.

I will keep you informed about ET compensation.

Chris