Allotments 4 All

 We have an ACER, (GREEN) had it for a while now.
It was growing well then collapsed asked at the local nursery for help he said plant it in ERICASOUS soil which we did.  It started to grow really well now it has collapsed AGAIN, can anyone help as to what is wrong with it before it gets thrown on the heap please. This is about the 4th time this has happened in as many years.  Do Vine weeval attack these shrubs?.
Thank you. Rosebud.

for us repotting acers the absolute killer is replanting them with the main stem below the level in the last pot. Does for them every time

As well as ericaceous soil they need very good drainage.