For UIID and TRIVE: these are free, so there's nothing to refund in the first place.
For an ATRIUM network: the flat $0.01 per user per month platform fee is billed on that basis. Closing your network stops future billing, but this help center doesn't specify whether a partial month is refunded — treat any part-month as non-refundable unless your invoice or the Terms of Service say otherwise.
Third-party costs are separate: storage, SMTP, payment gateway and video/SMS providers bill you directly and have their own refund policies, entirely independent of LINKSPREED.
Where the definitive terms live: legal.linkspreed.com publishes the Terms of Service, which governs cancellation and billing specifics more precisely than any FAQ can.
Before committing a budget — especially for a larger community or an enterprise agreement — ask [email protected] to confirm the exact cancellation terms that apply to your account. This is one of the few areas where it's worth getting written confirmation rather than relying on a general answer.