Well, XCI is the only private weed coin, had some issues with the initial implementation. With an old version some had issues with the big sized transactions - high mixin and maany small inputs making transaction size bigger than approved by network, say above 25kb for 1 transaction. There was a problem with an old wallet version. Old wallet was able to produce that kind of big transactions. If big transaction will reach a tx pool of network nodes it will stay there some time, about 24h. No miner will include that transaction in block and it will be deleted from tx pool. So after the sender will reset his wallet he will see his coins "back" like there was no transaction. That is why I am asking about the date of your transaction.
If it is not in blockchain - it is in your wallet.
You can send any amount of XCI with the new XCI Coin version. You should know that transaction size limit and block size limit is raising with time. 45kb at the present time. You will not be able to produce any bigger transaction to avoid network and blockhain flooding. As I said tx size limit is raising with time.

When you are reporting your issues, please, tell some specific info about your OS, wallet version, transaction details.