Hello Sayac,
Welcome to the community!
Sorry to hear you're having reception issues at that location. I understand the coverage map might indicate the area is covered. However, those maps can only ever be approximate coverage. The nature of cellular service is that it is dependent on being able to receive adequate signal from the cellular towers. Adequate signal would depend, in part, on your location relative to the cellular towers. In addition to your proximity to the cellular towers, there are also many factors that can affect cellular reception (see here and here). As well, different devices vary in their cellular reception. That's why no mobile provider can guarantee service. It's also the reason those maps can never be an accurate representation for all devices. There are just too many factors beyond their control.
Sometimes a better representation might be the location of the area cellular towers:
~taken from here.
Depending on your actual location in the area, some regions might be better covered than others. Unfortunately, if your circumstances don't allow for adequate cellular signal at your location, there isn't much that can be done. It's a common misunderstanding that any mobile provider will suit everyone everywhere. That simply isn't the case. Everyone's situation is different and what's best for one customer might not necessarily be the best for someone else. The relevant issue would be which provider has the best coverage for you. You might consider checking which provider might have more suitable cellular tower locations in those areas.
Hope this helps 😀
Cheers
