[nznog] Transfering DNS from other ISP's and other services - opinions needed.

Good afternoon all. I have recently 'acquired' (transferred) a domain from one isp to one i work for. From this transfer, a few problems arose - which where quite possibly (probably) due to my ignorance but i wanted to ask the list's advice/opinion. when i transferred the domain/zone, the other ISP canceled the email accounts also. My question is i guess - is this normal, what is normal, is this a general practice with ISP's as if it is maybe I could implement that process here. Thanks for any advice/answers.