Translation of Lätzchen

Luckily it didn't happen to me, my kids really grew up with us all the time. And besides, they are not allowed do that, because they are monitored endlessly. If they don't attend class they could find themselves on the next train going home.
Could you please read the following offers in a critical manner and confirm it before I will send it? I have also mentioned the warranty and the software in the offer, because it was requested by the customer.
Your German is really great. But you really need to practice more. What do you mean exactly? I'm 70 years old and retired. I live in Hamburg in northern Germany. It is close to the sea.