If you are Donator - Silver or higher, press F6 on the server, click on Settings, then on Change Icon.
This action should bring up a menu in which you may select a noncustom icon.

If you wish to upload your own custom icon(s) to the selector (available from Donator - Gold), you must create a ticket including a direct link to your icon(s).

Please note:
    • Your icon's size must be 32x32;
    • Your icon(s) must be transparent;
    • You may not upload an icon that already exists in the selector.
    • It might take up to 14 days for us to process your custom icon request(s) since all requests are processed in waves.

To become a member of the moderation team, you must be 16 years old with a minimum of fifty hours on the server you are applying for.

You can apply for Moderator on the forum, in the Apply For Staff section.
Make sure to read the Application Writing Guide, then fill out the Application Form.

This is most likely related to your dxlevel or workshop subscribes. You can try changing your dxlevel by typing mat_dxlevel 90 in the console.

As for invisible "weapon skins", try deleting Murder part 1 and 2 from your add-ons subscribes and clean your download folder from the Garry's Mod folder.

Unfortunately, our store does not offer any payment method other than PayPal at the moment.
However, we do accept Steam Gift Cards as a payment method.

This method requires you to—
    1) Contact the founder (Dimentio) on Discord;
    2) Send them your Steam Gift Card code.

Completing the above steps will grant you a reduction coupon with a value equal to your Steam Gift Card's value, which can be used to buy packages on the store.

Since the 07/19/2018 update, Donator points aren't required to purchase donator items — you may directly buy them using regular points if you own any Donator rank. 
If you have remaining Donator points, typing !convert in chat will automatically convert them all into regular points at a 1:10 ratio (1 DP = 10 RP).

There are two different ways to check your offenses — either In-Game, or on the website.

On the server, type !warnings in chat to check your overall warnings, both active and inactive.

To access your warnings and bans list on this website, click on your profile icon at the top right corner, then on Violations.
Alternatively, you can click here to access the page.

If you want to gift a package to another player, you must enter their SteamID in the Buy for someone else box, then click on Set.
This can be found on the detail page of the package you wish to gift, right under the Coupon box.

If you are unsure on how to proceed, refer to the picture below.