I need some advise about how to get 2D to do something about poor cellular coverage. I have repeatedly complained about cellular coverage issues near my house (inner city suburb in Wellington)

Multiple times I logged a ticket, and every time 2D makes me jump through endless troubleshooting: provide date/time stamps of multiple instances of missed calls/ poor call quality, swap sim cards, swap phones. Yes, all obvious things, which I have done numerous times. In the end, after wasting my time, nobody will acknowledge that the coverage here is poor and tweaking the downtilt on the antenna is not going to do the trick.  Friend with Spark have much better reception when visiting me (and judging by the location of towers, this makes sense). 

Other than switching providers, moving house, or buying femto cells (too expensive, plus why should I pay for it?), any advice on how to tackle this?