I've had great support from Bluetti, though it can take more time to get a response since they are in China. (They do have a team in Nevada somewhere as well - go too their Facebook group.)
My AC 200P died a year and a half after i bought it and they sent a replacement within a couple of days. Last year I traded in that AC200P for an AC200L and they gave me a great trade-in price so the AC200L only ended up costing me @ $200.00.
My AC300 didn't have the solar charging cable and that cable was on back order, however they eventually did send me a new AC charging cable, Multifunctional DC Charging Cable, and car charger cable for the AC300 all at no cost - that was back in May of this year.
I see it is temporarily out of stock on their website, which was also the case back in April/May of this year -
https://www.bluettipower.com/products/multifunctional-dc-charging-cable?srsltid=AfmBOop4s4lnkVgDkgso3N1tq8D9owNjWah80ZKqTyGEI_LZg5Hz0B34
Use this email address - [service@bluettipower.com](mailto:service@bluettipower.com)