SIM card issues

My SIM card hasn't been working for close to 5 months now,and everytime I call they tell me to do a SIM swap and I did that and it's still not working. This is not great, because this is the cellphone number I use for everything. Now I cannot access my stuff because I can't fix my sim card issues. Other SIM cards work great on my phone,so my phone isn't the problem. When I keep calling,the call centre agents are either impatient,or the phone just rings without answer. I don't know what to do anymore,and nothing is helpful