U700 does not react to the unlocking code

[Mach10]

My Samsung U700 model is not responding at all to the upper buttons inclusive the circle button I press on it. I can not enter the phone as it keeps asking me to type in to unlock the phone.

I have seen in this forum a code to enter, in order to reset the device. But I can not use the upper buttons (the lights for these buttons blinks as I press them but nothing happens), I only can type in the numbers and * and # into the field. Further I can not come. I have used several sim cards without needing to type a pin-code, but it still asks to type a code to unlock the phone.

I have used these codes to reset the device:

1 - *2767*3855# -> restarts automatically
2 - *7465625*638*00000000*00000000# -->> After this I can not press any buttons to go to the third part.
3 - #7465625*638*00000000#

Does anyone know how to solve this problem?

Thanks in advance.