Business ProfileforRainbow Air Cleaning Systems

So my friend did this referral program to show me the rainbow system and I was given the option to or to not buy it. They spoke to me about job opportunities while I was there and I wanted to earn commission if I worked with them. So I purchased the rainbow because they told me when I sell x amount Id get it for free anyway. I had to sign a cancellation by 1/4/24 and mail the cancellation to a business address in order to get a refund and cancel the contract. So I mailed the cancellation on that day. I went to their event that evening to see if this is still something I could vouch for and sell if I were to work there even if I dont end up using it myself, and I thought I could but I slept on it and two days later I messaged ******* to let him know I could not work for them and that the business who processes cancellations/refunds would probably receive my written notice like asked. He then told me that he would notify the department that I gave him notice two days late instead of the day I mailed the written notice like asked. He said they may not refund me then and Id be responsible for the $3800. Ive done everything as asked on the cancellation papers and I kept my carbon copy of what I signed and mailed to them. Now theyre saying theyre dating it as the post stamped date when I gave notice which I explained to them the mail was put in my personal mailbox by the cancellation date and I dont know what post office its gone to when they told me this. Now I keep calling and theyre blowing me off. So I need to be refunded and someone needs to get their equipment that I never even used.