Wi-fi router works poorly

[Evgenii]

Hello! Sorry for English, I'm beginner in German. 
About a week ago my wi-fi router started to work bad. Wi-fi connection is slow and unstable. 
LAN connection works fine. Probably the router should be replaced. 
I've asked the question via help contact form and I was told to ask for help here. 
Thanks in advance, Evgenii.

[pRo-Marco]

Hi Evgenii,

I will prove the connection and replace the router, if it is neccessary. Please send me your name, address and customer number by PN. Please also let me know here if you have sent the message.

Kind regards

Marco