I filed 2014-17 with 2018 SC return 3 weeks ago. I got 2017 & 2018 refunds and a denial letter for 2014 (too late), but haven’t yet received refunds or info for 2015-16?

[Opus 17]

Did you mail them in separate envelopes or the same envelope?  Did you get a tracking number and proof of delivery?

[aksmartin]

I mailed them in separate envelopes but all together the same day. No tracking, but I know they received 2014, 2017, and 2018.

[Opus 17]

There's no way for us to tell why they are being processed at different speeds.  You would have to contact the state.  (I find that the state tax people are more responsive than the IRS.)  

I would not re-send them unless the state tells you to.