Any person that knowingly receives or charges a rate of interest greater than that allowed under the Residential Home Loan Act shall forfeit the entire amount of interest that the evidence of indebtedness specifies. If any interest has been paid by the debtor to a person that knowingly received or charged a rate that was in excess of the rate of interest allowed under the Residential Home Loan Act, then the debtor may recover by civil action twice the amount of the interest paid plus his costs of suit and attorney’s fees. If any person, other than an institutional lender as defined in Section 4 [repealed] of the Residential Home Loan Act, receives or charges a rate of interest greater than that allowed under the Residential Home Loan Act, but such charging or receipt was under mistake or otherwise without knowledge of the violation, then the evidence of indebtedness is enforceable except that the lender cannot charge or receive more than the maximum rate of interest permitted under the Residential Home Loan Act, and the debtor may recover by civil action only the excess interest plus his costs of suit and attorney’s fees. Any action brought under this section must be commenced within two years of the date the evidence of indebtedness was signed by the debtor.