USSD codes do not work.
As topic, typing a simple USSD code gives me a feedback with a forever rotating arrow.
This seems to be similar to #7 (closed) and #11 (closed).
What works: report IMEI What doesn't work: ask the network for my balance. Also the code to do a top-up does not work.
Notice that the 'top up' code not only didn't show a reply, it also never got applied to my account. So my guess is that the code didn't get sent to the network.