Sorry to hear that Abuja didn't work out, that was the more reliable place to get visas for Angola for the past while for travellers heading south.
Not sure if there is any correlation, but the Nigerians also changed their rules at the end of January which makes it harder to get visas en route. For Angolan visas, all a person can really do is try to see if things have changed at the other cities where results have been traditionally less predictable than Abuja.
Last year at this time, I met up with some friends in Matadi who had success in getting their visas there. They had tried briefly in Kinshasa but moved onto Matadi as it seemed to be slightly better place to wait at the time. I'd try Dolisie first and then have Kinshasa and Matadi as the backup plan.
Maybe you'll have luck in finding another place that will issue prior to getting south, but those are the only cities that I have heard of with some possibility of success. If you are really organized, you may want to look into the logistics and process to send your passports back to your home country if all else fails. You can see the application process online by google search, some of the visa service agencies promise quick turnaround time but it isn't cheap and depends on your home country.
Hope it all works out and with luck, Dolisie will become the next go to destination for visas as Abuja used to be for people heading south.