I also had the same problem of not getting my transaction confirm then i saw that before this transaction one more transaction was pending, so first i accelerated through viabtc first one and then tried second one and both got confirmed. So you can do this way. from this forum time when the time comes 11.59 just start to use the viabtc acceleration it will get succeed correctly before 30 secs on next hour it gets confirm you can count timer from this forum timer as it is exactly working and i have tested it.
Sorry, I'm not sure if i get it correctly.. ? Do you made next transaction to push the first one, or there was one - oldone that you didnt seen before? But how it is possible to don't see pending old transaction? Which wallet did you use? (We are talking about old MultiBit Classic)
Edit:
It looks like you have right.. there was some old hanging transaction. Now he will try to push the old one and then we try to move the main one..
Thank you very much for your suggestion!