PIP tribunal won, but DWP not notified after a month, who do I contact?

Hello!

I won my tribunal appeal in February, and called the DWP today as it had been over 4 weeks since I got my decision letter from the Tribunal, but was told they have not received anything from the tribunal. I was told I should contact them to see what's happening, so I thanked the DWP person on the phone and went off to contact them. However, I can't figure out who to actually contact. I've got multiple different contact details for multiple departments all involved in the tribunal process. Should I use the number on the decision letter? The number on the website where I lodged the appeal? The court that held the tribunal itself? 

Has this happened to anyone else? Any advice would be appreciated!