Yes, if your debits have no TX ID, they went right back into the wallet. MPOS does not keep records of coins that are sent back in due to rejections. It is rejected because the pool does not have it's fee high enough to cover large amounts.

On the windows wallet you can send whatever amount you want. It will pop-up with a message asking you if you want to pay the fee. So it works fine. On pools, they are linux and it is a static fee that is set. Maybe someday soon they will implement a transaction fee setting that can pop-up for front end users on pools.