When you disconnect, your entire team is disadvantaged, that’s why the SR penalty system exists. You will never get your SR back in the form of a refund from Blizzard, and the system will likely never change.
See Overwatch Technical Issues, SR Loss, and Leaver Penalties for a longer explanation.
The hurtful bottom line is:
Too bad, if your internet disconnects you’re always going to be penalized for it and there’s nothing you can do aside from fix your disconnection problems.