Small but probably complex question about the interaction between manlands and Vedalken schakles.

Vedalken schakles gives me control over a creature until it untaps.

What if i take control of a manland?
At the end of turn, during the clean-up step, the manland won't be a creature anymore.
Do i keep the control over the manland if it's not a creature anymore?
If it's the case, If I untap my schakles on my turn, there is no creature anymore, so i'm wondering if my opponent gets its manland back.

Thanks for the answers.