That's a policy many companies use to force you to repair the system. It's the law in Canada, No fix, no gas. Laws vary according to the country you live.
The logic of the situation is you have a leak, if it's not repaired, the refrigerant will leak out and there is no warranty for loss of refrigerant because nothing was repaired. It's like adding air to your car tire when there is a nail in it. It may last a while....... then again it may not.
It would have shown good communications skills for the technician to explain this ahead of time.
1) to avoid the friction of misunderstanding
2) and have you sign a statement acknowledging that fact before adding refrigerant without a repair.
We give refrigerant credit towards warranty coil replacement if the replacement was done within 2 weeks, our warranty coil replacement price includes everything except the coil.
Any idea of a credit goes out the door when the home owner waits more than 2 weeks before making a decision and the refrigerant leaks out again with the resulting failure to cool. Some people will develop amnesia about the needed repair until the system fails to cool again.
Most customers are unhappy if you collect money and leave and their family is still hot and sweaty. I seldom leave anyone without cooling.
“I am for doing good to the poor, but...I think the best way of doing good to the poor, is not making them easy in poverty, but leading or driving them out of it. I observed...that the more public provisions were made for the poor, the less they provided for themselves, and of course became poorer. And, on the contrary, the less was done for them, the more they did for themselves, and became richer.”
― Benjamin Franklin