Roomba 620

Hi

I just bought a new roomba 620 after my roomba 520 died after 3years in service.

The new 620 starts fine but if I press the clean button when it is running then nothing happens, i cant stop it.
If it is charge with the docking station, then I can start it like normal afterwards.
If it has been charge directly with the cable, then it wont start. Then clean button just glow green but nothing happens.

I have to reset it, then charge it with the docking station before it works again.

I have tried to reset it, and I did the 72hour charging. But no change.

Any idear ?

There appears to be a charging issue with your robot. Since you just purchased it, we suggest that you contact the store where it was purchased from in order to exchange this product under warranty.

If it is giving any beeps also. If yes please check this link and try to rectify it. homesupport.irobot.com/app/answers/detail/a_id/641/~/list-of-roomba-500%2F600-series-error-codes

Else report the problem where you bought it.