Show result of prefix delegation

I’m trying to activate IPv6. I’ve a static range (/48) and my ISP tells me, that I’ve to do DHCPv6-PD in order to get it working… now, that’s what I did. Sometimes it works, sometimes not. And most of the times it only works with sample configurations found in the internet. My main problem is, that I cannot see what it did or if it did anything at all.
I’ve to establish an PPPoE connection. When I do this, then I can see that I got an IPv4 address assigned to this connection and I can see the entries made in the routing table, when it worked. That’s how I can check if IPv4 works over this PPPoE connection.
But… when I activate IPv6 and DHCPv6-PD on this PPPoE connection, I can’t see anything… what do I have to do? How can I see something? Which commands do I have to use?? (I’d like to see, if the prefix has been assigned to my router and which one it is)