what's wrong with my v3 and v4?

My v3 and v4 are both at child stage. They have only one bar filled in at their training and that's because I praised them when they where crying as a baby!They're never mischievious so how should the training bar fill up? Also, can I potty train them and if yes, how?
please help me! ^_^

No you can not potty train them and it's sort of random when they need praise or do something bad just look at them awful and eventually you'll catch them

Nope, you can't potty train these versions at all. Training times seem to vary by character and also due to some random variable. I've had almost back-to-back discipline calls and sometimes, I only have one call in an entire day. It's also entirely possible you are missing them completely for whatever reason. (Maybe the sound is off, the sound is on but you didn't hear it, or whatnot.) Keep in mind, training doesn't seem to matter as much on the v4s and up as I have gotten good characters with no training bars whatsoever. It's also entirely possible to max the training bar but they STILL call for training.

When your Tamagotchi calls for attention and it is crying, praise it. If your Tamagotchi calls for attention and it does not need anything (it does not have all empty hunger or happiness hearts), give it a time out. But you probably already knew that.

If you have another Tamagotchi of the same version, you can wrap a food or item and send it to the other Tamagotchi via the "present" feature (but it has to be with the SAME version). After you wrap the object in the "present" section under the 9th icon, you can send the food or item to the other Tamagotchi.

When the other Tamagotchi unwraps it, it may be what you intended to send, or it may be something else, such as a snake or jack-in-the-box. If your Tamagotchi did not send what you meant to send, the other Tamagotchi will be very upset and your Tamagotchi will be sitting on the screen with a really weird expression on its face. Give it a time-out and you will get a training point.

If your Tamagotchi did not send a bad gift, wrap another gift and try again.

You have to wrap gifts yourself for this, you can't just select "present" when connecting and let it send any gift. You have to determine what gift it is supposed to send and discipline your Tamagotchi if it sends the wrong gift.

Hope this helps! Trust me, this process is easier done than said...