Ralis has now asked me for 5000 septims for the excavation which I have paid. However it seems like forever and there is no courier delivering the final note. I gather from UESP that there is a final note and when I visit Kolbjorn Barrow I am supposed to battle Ahzidal.

Don't know whether its me getting more impatient or whether something broke but yeah, I have been traveling all over the island from Skall Village to Raven Rock and not courier appears. For the earlier notes I recall the courier appeared quite promptly. Is there any known bug on this issue?

On a separate but related note, what's the pros and cons of sparing Ralis' life? I generally don't like killing ppl but will keeping him alive cause "problems" for my character in future? Maybe I've watched too many movies but I guess its the fear of what if I let him go know and he returns to back stab me in future? Yes he claims he was being controlled by Ahzidal but who knows?