You could have called a rollback instead of driving it knowing it's not right. Unfortunately, a self install opens the door to negate warranty claims. Most mail order engines and transmissions in the warranty fine print will contain the terms "to be installed by licensed facility" and you're not even sure you got the converter in it correctly. If you did not have to pull the converter forward to the flexplate to get the bolts in it then the converter was not fully seated. This can damage the pump and converter. It was a new converter correct? Only you were there. If they did the install they would have caught the leak before it left the building. Even a pro makes a mistake once in a while.
Hopefully it's not that serious and they help you out in some way.