How to claim my EOSB if I moved with the same company from the UAE to Germany?

I moved from the UAE to Germany under the same company after working 7 years in service in Dubai. Before I moved, I asked for my gratuity.

The company refused because it seems that the gratuity is payable on termination only, not on transfer within the same company.

The company asked me to sign a letter to waiver my gratuity in exchange for "years of seniority" in Germany of the same years that I served in Dubai.

Did I make a mistake when I signed that letter? Is this normal?

"Years of seniority" means nothing actually.