Sonoff Mini Flashing?

Hi

After having read bunch of different tutorials and different procedures, I’m still unable to get anything from 3 Sonoff Mini bought in April last year ! All three when I power them jjust blinks blue every 2/3s. If I maintain the plastic button on it, even more than 5 or 30s, no changes in the blink. If I try to pair them with EWelink it’s not working and have never seen too the ITEAD-XXXX Wifi AP or succeeded to get it to connect at my AP setup in Sonoff diy mode…
Any ideas ? I don’t expect 3 of then to be dead :confused:

Thanks

Vincèn