Yo. Get ready for Eva to direct you to the Introduction forum 
As for Raziel… Arzel is an excellent and easy angel to contact that can grant quick access to Raziel.
Furthermore, SINGING angel names is a tip I’ve picked up from Damon Brand that works amazingly well, so make sure to sing their names. Doesn’t matter if you suck at singing, just try.
Usually this is enough - singing Arzel and after a few minutes asking him to connect you to Raziel, and then singing Raziel.
If you want to make 100% sure, get your hands on Raziel’s sigil. No need for Arzel’s, he’s really easy to contact.