Equifax, a debt-collection agency, sent Donna Russell a notice about one of her debts. The front of the notice stated that [i]f you do not dispute this claim (see reverse side) and wish to pay it within the next 10 days we will not post this collection to your file. The reverse side set out Russells rights under the Fair Debt Collection Practices Act (FDCPA), including that she had thirty days to decide whether to contest the claim. Russell filed a suit against Equifax. The court ruled against Russell, who appealed. On what basis might Russell argue that Equifax violated the FDCPA