Not reliable / trustworthy
Before You Begin
Pause and breathe. Even if this shouldn't be happening... accept that it is and embrace it with composure and calmness.
Calmness is the only way forward because without calm, there is no possibility for receptiveness and connection. Your child won't give to you any more than they see from you.
Never forget that a strong connection is fundamental, as there will be no correction in them if there is no connection with you.
The Core Problem
The child doesn't understand the negative impact they have on themselves and others when they let down those that were relying on them.
What Will Make It Worse
Reacting with frustration or criticism or labeling them as "unreliable" won't make them less likely to do it again.
What The Child Needs
1. To learn how the idea of trust rules our lives: Teach the child that trust is a very important part of the relationship we have with our family and friends. A trustworthy or reliable person is given more respect because trust takes time to earn and can be erased with a single bad act. Every single day we put our trust in others that they will help us in the way we need it, and we must recipricate. If we are seen as untrustworthy, not only will others not have much respect for us, they won't partake in a relationship where only one side is doing their part.
2. To take the steps to rebuild lost trust: Explain that trust can be slowly rebuilt and allow them to do so by appologizing for what happened, fixing what is fixable and following through on future responsibilities.
3. To feel pride in accountability: Help them feel a heightened sense of pride and maturity as they successfully handle their responsibilities and fulfill commitments.
How To Have The Conversation With Your Child
Find a private place where you and your child can sit and chat, free of any distractions.
Share with them that there is a lot to love about them, but right now, not being reliable or trustworthy is becoming a big problem. It is bad for them and those that count on them.
Tell them that rather than giving them punishment after punishment, you want to have a serious talk about why people make such a big deal out of trust.
Talk through points 1 and 2 under "What The Child Needs" with the goal of re-framing in their mind why trust matters in life, and making a plan of how to get it back now that it is something that matters to them.
In the days/weeks following this conversation, praise them as they make up for the past and exhibit a clear positive change in their reliability.