Just get a merchant account and program it yourself - it's super easy to do. I don't even understand a need for 3rd party recurring billing companies - programming something to charge someone $X amount every X days is pretty dang easy...
+ What if we change gateways?
+ What happens when someone gets a card declined for an unspecified? Retries? What if the error was fatal? Sends an email? Does it cut their service immediately or after a grace period? If they pay on day 2 of the grace period, do they get 30 days of service or 28?
+ What happens if someone wants to upgrade from the $29 / mo account to the $79 / mo account on the 4th of March if their anniversary date was the 25th of February in a leap year?
+ A bug screwed up Bob's data and we're offering him $125 of credit to say we're-so-sorry. You built that feature, right?
+ Our accountant wants to know "How much have we billed this year?", "How much have we collected this year?", and "How much money have we collected that have we not earned yet?" You built that, right?
+ Foo Corp filed a chargeback against payment #123456. This means we got a callback ping and did something consequential as a result of it, right?
+ Why are you answering these questions when you could be writing code that people actually pay for?