Probably unrelated to any WA carts, but this week, I had a client complain of the same issue just using PayPal links, not Webassist. Related information is that many cell services were down. Unless you can recreate issue, hard to solve. My client could not replicate the issue.
If it was me, I'd set up a $1 product and test myself on what is happening.
Your post is too vague to garner response so until you share more details, I suspect help won't be forthcoming.
Share specifics, ie, site, links to cart, type of cart etc.
