Blackwidow keyboard : few keys repeting themselves

Hello! I am new here because I recently had an issue with my keyboard. A few keys (mostly "a", "c", and "b") repeat themselves a few times (2 to 4 times) when I press them, but not everytime. It started very rarely with the b (maybe 1press / 20), but now it is getting very frequent (like 1/4 for the b, 1/6 for the a...). It's really anoying when I'm trying to write stuff (I am actually writing a memoir, so the pain is huge). Do you know if it could be anykind of software issue, or do I have to change my keyboard? I bought it like 4years ago. I also tried to clean it, but nothing changed. Thanks for your help. Have a good day