How dangerous can oil ETCs be?


I recently bought this leveraged oil ETC on European markets. So far I've seen an increase in value. My question is if these kind of ETC's also can become negative and force me out like it happened to many that got margin called while handling with Oil futures that dove into negative area. So my question is if a loss greater than 100% possible with these ETCs?

Also if I understood well, there is no such thing as a delivery date with those ETCs before which I should sell if I am not interested in exercising my right to buy oil. Is that correct?
Any Updates???