I don't believe OnePlus has any affiliations with carriers at this time. The demand for their devices is very low compared to the more well known brands. They also had issues with having sufficient stock in the past. OnePlus is pretty unknown to most users since OnePlus doesn't appear to advertise their devices.
I know many people on TELUS with One Plus devices , its a sham they won't carry these phones. I spoke with someone in the office the president and he had others inquiring about OnePlus on TELUS. He said he would look into it.