This is good to hear. The port 25 block is frustrating and inane, as it stops customers using anyone else's SMTP servers. We have clients contact us who have been using SMTP on port 25 to our servers fine (not many use non-SSL but still a few for their own reasons), then suddenly one day it stops. It appears some Telecom ranges have port 25 blocked, others don't.
My understanding the block is the default for every connection. If you want to use port 25 you fill in the form online and they will remove it for you.
This was my understanding - however it's not the case. We have clients on Telecom connections who have had no issue for years, then suddenly can't send via port 25 one day. Others have been moved to alternative ports due to being blocked, then a new computer is purchased, the default port isn't changed and port 25 works again.
As said earlier - it's hit-and-miss.
Sounds very unusual. The only possible thing that could have happened is when they moved to the new Broadband stack off the old one their plan didn't get correctly moved across to include unblocking of Port 25, which can sometimes happen. Plus it is known to happen when people move to a larger plan or have interleaving turned off as that can cause the port 25 to get turned on again if the CSR doesn't notice what current plan they are on.