It’s not a fault it is a failure in capacity planning. I’ll expand on that I used to be a network operations centre shift manager and we would be the poor suckers that would get in the neck from the customer contact centre, service managers, end users/customers when there was congestion on a part of the network that could have been avoided if someone had thought ahead a bit more.
Saying that with a mobile network the RAN’s can be in out of the way places due to coverage/tin foil hat/commercial reasons etc.. So it could be that planning did their job in plenty of time and placed an order of additional backhaul/more antenna and so on, but their 3rd party supplier is dragging their feet delivering it, either due to being useless or planning/wayleaves and so on.
Second the suggestion of the Femtocell, if you are nice but firm it has been known for mobile providers to send them out free of charge.