How do I stop iTunes deleting my playlists off my phone

Thanks for reaching out MadLamb,

It sounds like your device might be automatically syncing when connected and erasing your playlists. We can help.

A great way to prevent syncing of your device can be found in the article, Sync iTunes content on PC with your devices:

Keep items from being synced automatically

If there are some items you never want synced (for example, if they’re too big to fit on your device), you can keep them from being synced.

You can also turn off automatic syncing for music, movies, and TV shows. You must do this if you want to sync iPod classic, iPod nano, or iPod shuffle with more than one iTunes library, or automatically fill your device with songs using Autofill (see the next task, below).

Note: To sync content from your computer to iPod classic, iPod nano, or iPod shuffle, use iTunes on Windows 10 or later.

1. Connect your device to your computer.

2. You can connect your device using a USB or USB-C cable or a Wi-Fi connection. To turn on Wi-Fi syncing, see Sync iTunes content on PC with devices on Wi-Fi.

3. In the iTunes app  on your PC, click the Device button near the top left of the iTunes window.

4. Click Summary.

5. Do any of the following:

- Keep individual items from being synced: Select “Sync only checked [items].” Then deselect the checkbox next to any items in your iTunes library that you don’t want synced.

Note: If you don’t see this option, choose Edit > Preferences, click General, then make sure “List view checkboxes” is selected.

- Turn off automatic syncing for music, movies, and TV shows: Select “Manually manage [items].”

6. Click Apply.

Hope that helps.

Take care.