I've had to contact them twice. Both times, I used the Contact form on the website. Here are the results.Let me put it this way.
1. Has anyone ever had them ACTUALLY respond to a support e-mail?
2. How many days/weeks/months did it take before they replied?
1st time - I received a game with a broken case. I emailed them about it. They got back to me in about four days, telling me they were sending a new case. Received two brand new cases.
2nd time - I redeemed for a code for PS Plus. It was a while before I tried redeeming the code and when I did, the code had expired. I emailed them about it to no response. About a week later, I emailed them again, saying that it was really frustrating that they hadn't replied. That day, they emailed me, claiming to have not received my first email. They told me that the code did indeed expire and then offered to either refund me, or allow me to have any time I wished. I chose Ratchet and Clank, since I missed it during that whole debacle.
These are just my experiences. YMMV