EE contacts being charged a fortune to call me whilst in the UK - why?

Hi, some networks take a more leniant approach, others can charge what they wish and that is why we don't publish rates but ask people to check. Our focus is on providing you, as a traveller, the SIM to save money - low cost outbound calls and free inbound. The large networks see it as an opportunity to profit unfortunately, hence their charges - they don't need to charge a premium but some do. We are always on the look out for a SIM that is cheaper for calling in to but there are none available that meet our brief.