Very little stitching to keep batting in place

The comforter arrived with a small stain, sort of like a print pattern transfer. We washed it before putting it on the bed, and the batting inside the comforter gathered as lumps. There is very little stitching to keep the batting in place. We have tried to smooth out the batting lumps with partial success. What's to keep the batting from lumping up even worse next time we wash it? Returning.

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