Deleted play store accidently form my rooted Sony Xperia C2305 using lucky patcher
If you are running a custom ROM, you will need to re-flash it along with the corresponding GApps package.

If your phone is unmodified stock (beyond rooting) you will need to re-flash the original phone firmware as described in this guide, and optionally re-root it.

Quote of the guide from the above mentioned post:


  *Download wmshua
  *Download ftf file of 16.0.B.2.13 or ftf file of 16.0.B.2.16(preferred)  (these files are specifically for Sony Xperia C C2305), If you have any other deivce, download their firmware files.
  *Install Sony PC Companion
  *Switch Off your mobile phone and get the Original USB Cable pf your device
  *Open Wmshua and then Connect your device to PC pressing the Volume Down Key
  *As Soon as connected Wmshua will install device drivers (taking about a minute), then go to "Flash" option and select the ftf file from
  there. And click on Start. It will take about 10 minutes or maybe more
  to flash the file. Wait Till It Completes.
  *Now your device is ready on 16.0.B.2.13 or 16.0.B.2.16 whichever you selected