Sony xperia m2 problem

[W St]

Unfortunately, the google play store (now installed is v 4.9.13) does not connect to the internet. Message: "Connection timed out" / "No connection". This problem started after v 4.3 or so. Android v 4.3+. I once set back the firmware by means of this option inside the cell phone, but since I don't have any apple or windows computer, I can not make a back-up of the device, so I don't want to reset the device again. I can download apps by using the browser but they never show up in my telephone. This problem does not occur on my tablet computer with android v 4.2+.

Any solution for this apart from device reset to factory settings? Thanks.