Mogul power button issues

[NBAKING23]

The power button on the side never shutdown my phone completely it only puts it in sleep mode. I had no problem at all for several months shutting down my phone with the powerbutton until this issue occur. I believed somebody a while back had a problem like this in another forum and they was able to solved this issue (I cant remember which forum). I was wondering if there is a possible cab or someting I can used to be able to turn off my phone when I need to??

thanks in advance