Well I will tell you that to the best of my knowledge - as someone who both worked here and had foreign workers working for the company - I am not aware of there ever begin exceptions to those contributions. Yes, taxes are a different story as there is a minimum requirement of salary. If you don't exceed it, it's up to you to file and/or pay on your own if required. If you exceed that threshold then the company must withhold taxes on your behalf. But that 17% is (or was as of 2013 so things may have changed) completely mandatory for the company to withhold.
Best of luck. If your company gave you the certificate - then they should be able to help you work though it via their local HR/Accounting. Perhaps there is something new or not widely known but my gut says it's probably not going to happen in re you getting that 17% back.