If they have enough resources to manually phone people to extract their money then they have enough resources to manually make out invoices and manually email them. So the "IT issues" argument is rubbish. Sounds more like incompetancy.
Now that is a statement that makes no sense.
Most people can make a phone call, I'm pretty good with computers, networks, etc. but that doesn't mean I could look at the two CRM systems and their databases and start to migrate one to the other, or both to a new system, or even extract the data out of an unknown database but, I can definitely make a phone call.
You don't know how much data has been transferred so far, and to make out thousands of manual invoices and then enter them later, rather than take the payments over the phone and enter the details into their system is probably easier.
So, the manual bit is nonsense.
You're just bitter and twisted about something I think.
Live with it that's what business is about, companies come, go and get taken over.
At least neither of these schemes allow totally unqualified and un-assessed operatives to do work under the banner of their scheme.