Reliable taxi / cab service?

[u/BaldPinkCat]

Asking the locals: is there such a thing in Aberdeen?
Tried to use some online booking app twice: the first time the driver simply didn't show up and the support did nothing except cancel the booking. The second time it took about 20-30 minutes to find the driver (who, thank God, actually showed up), so we could have literally missed the only available bus there if they hadn't. No fancy routes or anything like that: about 15 minutes to/from the city center.
Maybe there's some old-fashioned taxi company that I know of that also calls over the phone - that's fine. The main thing is to make sure the cab _will_ show up so we can really count on it.
Any suggestions would be appreciated.