Can’t make calls

Same here. Just spent an hour on chat asking me to reset network, change APN etc, all things I’ve tried already. 

Then suggested that it’s a faulty SIM and to order a replacement which means losing all access to your phone as they block the number until the new SIM is activated.

Why doesn’t Smarty just admit that calls are being lost due to congestion. They don’t or won’t pay Three for sufficient capacity for their customers. What other company could get away with providing a service that is never fulfilled because their hiding the truth of lack of capacity from their paying customers?