We have secured direct relationships with 220 carriers globally essentially skipping the aggregators. That way in terms of support in almost all cases we can at least explain what happened with the message end to end.
Yes, we run our own SMSC but in terms of functionality like routing and quality control we go way beyond what a normal carrier would be able to. CLEC is a US specific term and not needed to sign direct agreements with carriers. We operate our own SS7 stack, global titles and mobile network codes. This way we can interconnect with carriers as a carrier. Deploying an on-premise SMSC or E1's would be an old-school way of doing this. Most carriers use either Sigtran or connectivity through their SCCP provider.