Daily Missions

Not sure if this requires technical support, or if it's just my horrible luck continuing.

Ever since the 8th day after the daily missions started, I've needed the first s to complete it.
Still, yet to get it. I've completed nearly all the missions since it started, but still no s. I wouldn't care so much if they stacked up, or you could trade in ten of one letter for one of another. I've talked to some people who have turned them in two or three times.

Any ideas on why I would be getting letters I already have for more than a month.