Spotify keeps deleting downloaded songs

[Noeta]

Hello everyone,

I noticed scrolling down the forum that this is a very common problem without a real solution proposed so far. 

Spotify keeps deleting my downloaded songs. I tried all the solutions proposed by others users but nothing works fine:

1. Disconnecting all paired devices;

2. Erasing cache;

3. Re installing the app.

Just for clarification:

1. I got a lot of free space on my device;

2. I got a Huawei P9 life;

3. The problem started more of less one month ago. I am on Spotify for at least 4 years and I haven't had such kind of problem before with all the devices I used. 

I really need this features, without it this app is practically useless for me.

Any advice? How can we get this problem to Spotify in order to solving it?

Thanks for your help