Sorry to hear your sim cards ar not longer working in your phone.
Repair and support response time dependent on where you bought your phone.
Most resellers respond within one working day. I will expect the reapar wil be done within two weeks.
for accurate informatie you will need to ask your reseller.
Fairphone seport have a average response time of 18 working days (live chat goes faster), i dont know about the repair time but expect it to be longer than two weeks.
you can check the information wiki about Fairphone suport for more accurate information.