I've been in Top 10 raiders for years now, and I've never had a problem with this. Possible causes:

1. You're out of raiding attempts (not very likely).
2. You raided them last Monday by server time, not your local one (very likely).

You can check #1 on the map and #2 under "Enemies" tab in "Pillage & Plunder" (but you need to do so before the reset). Alternatively, raid them again after the reset. If it gives you the res, your problem was caused by #2.

If neither of these helps, please specify which platform (Plarium (app included) or FB) and server (The Pirate Bay/The Golden Coast/Sirens' Strait) you're playing on, and at which coordinates.