All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and messenger.
First of all, we advise you not to worry about this matter because the falling of the wall may have been caused by heavy rain, so you should say, "Indeed we belong to Allaah, and indeed to Him shall we return.", be patient and rejoice over the promise of Allaah for those who are patient when they are tested through their wealth and children; Allaah says (what means): {And We will surely test you with something of fear and hunger and a loss of wealth and lives and fruits, but give good tidings to the patient, Who, when disaster strikes them, say, "Indeed we belong to Allaah, and indeed to Him we will return." Those are the ones upon whom are blessings from their Lord and mercy. And it is those who are the [rightly] guided.}[Quran 2:155-157]
We also advise you to regularly recite the reported invocations and supplications for seeking refuge in Allaah and protecting oneself from evil matters. It is permissible to perform Ruqyah against magic and similar matters, as Ruqyah is prescribed for a person who suffers from an illness but also for someone who is safe and sound (as a means of prevention).
For more information on the treatment of magic, please refer to Fataawa 84498, 82918, and refer to Fatwa 162951 on how to protect buildings under construction from the evil of magic.
Allaah Knows best.