I'll start with I play on PC and I don't use any mods. I started a new character for the event, a single female living in Willow Creek. I was able to do the event through the planting of the flowers ...
Ideas
I am still having this problem as well. I never was shown tasks to complete for "A Call Away." I initially got the newsletter in the mail, and it disappeared as soon as my Sim read it. I have not been able to progress at all from that point. I never have had the option to expedite the mail service. I have tried buying a new mailbox, and even moving to a new lot or using a different saved game. Each time my Sims receive mail again, they have the option to Get Mail, and it says everything is collected from the mailbox, but when I check their inventory, nothing is there. I'm so disappointed that I haven't been able to make any more progress.