Why do call centre agents ask for passwords?!!

I called DStv because I needed assistance with something. During the call, the guy who was assisting me asked for my dstv account password. Is this procedural, is this safe, shouldn't they have access to everything on their end anyway. Anyway the email linked to that dstv account got hacked shortly after. Why do dstv call center people have to ask for our passwords??? I'm so upset because I think that guy had something to do with the hacking.