Roaming disabled bug on 4G and LTE
I have an iPhone 6 and my phone operator (TIM Italy) billed me 7 times for connections I made abroad. The data transfer was minimal, just a couple of MBs in total, but the bill was high as I pay a fixed price for each connection done abroad, regardless of the data transfer amount (until a certain cap is reached).
I have the roaming option disabled on my iPhone so I didn't expect any data transfer to occur.
I tried to fill a claim to get the money back, but my operation replied saying that they have proof that connection happened and they are saying it is a pretty common case with iPhone 6 and 4G/LTE networks. They are saying the software roaming lock works well for EDGE and 3G, but for 4G/LTE it sometimes allows some data to be transferred, thus the billing occurs as they can't distinguish voluntary from involuntary data transfers.
My operator is suggesting disabling 4G/LTE to avoid running in the same issue again, but it is not an acceptable solution to me as I live on the borders between Switzerland and Italy and I often fall by chance under Swiss network coverage so either I disable 4G forever or I have to accept with those very high bills.
Is Apple aware of this bug? If this is a software bug can I ask Apple to refund my bills?
iPhone 6, iOS 8.1.2