Internet speed is unstable and low

[777]

I have problems with internet speed from day one. Cannot use continuously smart TV and mobile phones connected to the vlan. They came and fixed something few months ago, but this doesn't help. Download speed which was contracted is 200Mb but many times I have about 2Mb. Also it disconnects and then there is no signal. Sometimes it writes authentication error, some times not all 4 green indicators on the vlan are seen.
I reported error 15th Feb. but nothing happened since then.
I have a standard Kabelbox.

[ERFD]

Hello, 777,

please send me once your customer number, address and your date of birth by private message. I like to look for the cause for the disturbances. Is the speed bad at certain times? How often do WLAN failures occur?

Best regards Fred