@calm
Sorry, you do not understand to basics, if you have moded block with phone outside #contact_form, then you need to change CSS as well. Please find some developers to do such work for you.

@frosticek
yes, i'm just learning this all. now, I even dont understand where is my mistake - because I told You before what Im doing even few times.   
I'll consider about hiring developer for that css changes.
thanks for support, time and patience.

if there is anyone who can clearer explain, point or guide for dumb like me, please, write. 

@calm
In this code:
<?php if($mobile_found && in_array(osc_item_category(), array(104)))  { ?>
  <style>
    #contact_form .phone {display:none!important;}
  </style>
<?php } ?>
 
                    <div class="phone<?php if(!$mobile_found) { ?> no-number<?php } ?>">
                      <a href="#" class="phone-block" data-item-id="<?php echo osc_item_id(); ?>" data-item-user-id="<?php echo osc_item_user_id(); ?>">
                       


This part:
#contact_form .phone {display:none!important;}
Should be probably changed into:
.phone {display:none!important;}
As I cannot see div with ID #contact_form anymore.


+ condition:
<?php if($mobile_found && in_array(osc_item_category(), array(104)))  { ?>

should be changed to:
<?php if(in_array(osc_item_category_id(), array(104)))  { ?>


"As I cannot see div with ID #contact_form anymore."
if I understand right -hmm, my site is clean, - I have made css modifications, but that modifications didnt touched item.php.  And I checked with 'beyond compare' my actual item.php with untached veronikas item.php - I cant see any #contact_form which would be dissapeared in my actual item.php. (?)
now Im trying to understand Your code. before I was thinking, that I understand css basics ok.

thanks for Your extra support @frosticek! works like a charm!