Default [Q]Root CAT B15 FW 4.1.2 - failed swaping storages

Hello,

My problem started when I wanted move apps to external SD on android 4.1.2 - the Catepillar B15 has 2 storage named " Internal storage" 1GB and " Phone storage " 1,5GB. I bought SD card 8GB

I found some forums and the people wrote about swaping. :

"
1. root phone
2. install Root explorer
3. Open /etc/vold.fstab

change this:
dev_mount sdcard /storage/sdcard0 emmc@fat /devices/platform/goldfish_mmc.0 /devices/platform/mtk-sd.0/mmc_host
dev_mount sdcard2 /storage/sdcard1 auto /devices/platform/goldfish_mmc.1 /devices/platform/mtk-sd.1/mmc_host

to this:
dev_mount sdcard /storage/sdcard1 emmc@fat /devices/platform/goldfish_mmc.1 /devices/platform/mtk-sd.0/mmc_host
dev_mount sdcard2 /storage/sdcard0 auto /devices/platform/goldfish_mmc.0 /devices/platform/mtk-sd.1/mmc_host

This swap the memories.
"

I did everything.:
1) rooted phone by " Kingo Android Root "
2) downloaded root manager and also " Busybox "
3) I made a change in vold.fstab
4) Restarted the phone - after that I lost "Phone storage" and " SD " . Phone couldn't find them and a lot of apps have not been able to be opened. And I also couldn't download and install apps from google play because download direction.
5) I made factory data reset but still same problem - one change = I was able to install apps from google play, so I installed "root manager" and "busybox"
6) I changed text in vold.fstab back to original and restarted phone - no change
7) after factory data reset still no change
8) I also unrooted my phone back by " kingo Android Root "

My situation :
I) I have only " internal storage "
II) I can see folders " sdcard " and " sdcard2 " but both are shown as empty
III) I can download and install apps from google play
IV) I'm not able to download things but browser, because of no valide direction

Does anybody know, How could I solve this problem? Don't need to move apps on SD anymore, more important is get back normal status, like it was before I started with root

I have no back up :/.

I was thinking about firmware update somehow. But I don't know if some update is for B15 and not sure if would that work.