Can I sue a furniture store for an item I paid for

Hello I paid in full for a dining table from a company I found online in February 2022. They have promised me every month that it was going to ship and that it was in the “inspection” phase. I have patiently waited for months constantly pestering them about updates because they couldn’t seem to update me on their own. September 2022 I lost patience and told them I wanted to cancel my order for a full refund. They still said it was ready to ship, although with my experience I knew it was a lie. They then sent me a docusign form claiming they will reimburse me for the full amount, which I signed. Three days later they send me another docusigm form stating they will reimburse me a partial refund removing $51 for no apparent reason. I checked their website re reading the cancellation terms many times and have no read that they do partial refunds for any canceled orders. I am sick of this company and their lies and would like to sue in small claims court, but don’t know underwhat grounds