Billing selection for provider

Became before choosing a billing for a network of 1.5-2 thousand abons. At one time, I had a chance to try Stargazer and UTM, Stargazer for a network of more than 100 people I do not advise anyone to use, it takes much more time to fix bugs than to write a new billing, UTM-ka was probably the most stable and universal tool in almost a half of local nets, and without taking care of the purchase and license earlier for a network of 300-400 abons, also used broken UTM.
But now I work in another IT company and the question of free or broken billing is not worth it, you have to buy it, but you don’t have the money as always, you need to keep within 2-3t. $ UTM just disappeared as the price with the functionality you need goes far beyond 8t . $

After a long search on Ineta, I came to the conclusion that abills is the best billing for adequate money.
the biggest plus is open source, and in the case of termination of support by the manufacturer it is easy enough to understand and add the necessary functionality,
+ A fairly large set of additional plug-ins significantly expands the possibilities.
+ support for telephony and TV
+ I did not find an adequate negative about him, although a lot of positive reviews.