extremely soft 2nd to 3rd shift

If i could go back to the moment my transmission first burnt up, i would have just bought a brand new transmission and installed it myself, letting these guys re-build my transmission was a huge mistake. I have had nothing but probems with it. First one being that they instaklled the wrong torque converter, They fixed that free of charge, the second one being they gave me a different dip stick and dip stick tube wich was reading the fluid level wrong and there fore fluid was pooring out of the vent, They fixed that issue free of charge and now this shifting from 2nd to 3rd gear issue. Thats 3 different issues in 18 months. All i know is he better not argue with me when i bring it to them over this shifting issue.
I'm going to call him today and let him know whats going on, and make an appointment to get it checked out, I'm sure there is pressure tests they can do to determine if there is any issues inside the transmission and they can drop the pan and check out the valve body, and while they are at that they can install a shift kit. Just havent decided between the tfod-jr or the tfod-hd2, i dont need anything too radical, but i would like some firmer shifts. Maybe i should just tell him to do his own magic to it to get it to shift firmer.
Since the owner told me he dont care for shift kits because he can do modifacations to the valve body himself to get firmer shifts, so i guess i will ask how he feels about installing one, but first i want them to look over the transmission and make sure there isnt any problems with it and if there isnt then let them install a shift kit or do some tweaking on it or whatever.
It just frustrates me that i spent 2500.00 bucks on this transmission and it cant even have over 5000 miles on it yet and it just wont stay consistent. Maybe its just a cable adjustment, i Just dont know.