The answer depends on where you have accrued your pension entitlements, due to the different financing methods in western and eastern Länder, Please distinguish between the western (8.1.) and the eastern Länder (8.2) in Germany:
7.1 In the western Länder
You can only get your share of contributions refunded in the western Länder, if you have not fulfilled the qualifying period of 60 months. Otherwise, you are entitled to a pension and will benefit from it once you have retired. Pensions can be paid out worldwide.
Should the qualifying period not be fulfilled, please note:
It is possible to apply for a refund of your own (not your employer’s) contributions. Please send an application to the VBL before you reach the age of 69! The refund will render the insurance null and void. Consequently, in case of possible future contracts in the German public sector the insurance will start anew. Service times cannot be reinstated!
Recommendation: You should be sure that you won’t return to Germany to work in the public sector again before you apply for a refund.
7.2 In the eastern Länder
Should you not have fulfilled the required qualifying period of 60 months, you are still entitled to a pension, which only bases on your premiums in the VBLklassik in the eastern Länder. Therefore, you cannot claim for a refund of your paid premiums in this financing pool. Should you leave your employer before being entitled for the full pension amount (based on your and employers’s share) you retain your accrued pension entitlements until you retire. If your pension entitlement ends up to be less than 29,05 Euro (western Länder) and 25,20 Euro (eastern Länder) per month (value in 2016) you can apply for a lump sum payment instead of a monthly pension payment.