I think both clubs are at fault.
This wasnt the only deadline deal that fell through right? Großkreutz-Gala case was even more ridiculous from what ive heard.
This happens quite often actually. Simple solutions: Do your business earlier.
In my life I have always tried to handle things with a certain deadline as early as I was possibly able to do it and while it didnt change a lot most of the time, because I would have also done it shortly before the deadline anyway, but there were several occasions where I spared myself a lot of trouble because of unexpected factors that could have been actual problems if I had done it later.
Do your fucking business early on, and then relax, its very easy. They were in negotiations for months, even before the transfer window, its absolutely not understandable how they could have taken so long to find an agreement and sign the papers.