Auto-sleep function too short

Before buying I have read some reviews and could make friends with the problems described therein.
When the keyboard was there, it was also tested immediately. As it turned out very quickly that the keypad after 5 seconds without pressing a button probably goes into auto-sleep. If you continue typing immediately goes well without any major problems. If you wait a further 2 seconds, it takes about 5 seconds until you can continue typing. This is in my view for the Mitsch Rieben at lectures, which I would use the teblet, completely useless. If you start typing after one has written a few words, until the tablet responds. Not suitable for my project.
Sichterheitshalber demand from the seller, whether you can switch somewhere, the instruction manual is no help.
From the seller unfortunately only came a standard response that you can exchange it or get the money back. Have it sent back and get the money back with no problems.