Rod,
Sounds like something was out of alignment when it was installed. I say this because you didn’t say you had water in the oil the first time. Question is was the seal just put in wrong, was the seal wrong or the shaft moving after it was repaired.
You have to find out what went wrong in the out drive. Was it rust in the bearings, alignment or something bent? I have seen a lot of guys draw something in when it won’t go and 99% of the time you can’t do that. It will bend or break something. It could be just a bearing went bad and the rest is history. Unfortunately it is hard to tell if everything is in good shape unless you take it all of the way apart and look. I assume they did not do that, just spin it and if it feels smooth, and then you have to go with it.
The best thing is make them show you what locked up in the drive, then you can find out if it was something they did or something just went bad.
If it was me I would wait for the call and tell them you will right down to take a look. Make them show you the bad part and go from there.
Good luck
Rick