DUNLETH ENTERPRISES (PVT) LTD obtained banking facilities from FBC Bank Limited (the respondent). As security, the respondent obtained signed guarantees and deeds of hypothecation over immovable properties from the appellant and three other sureties. The appellant was not a director of DUNLETH but was related to one of its directors, Duncan Mukondiwa. The appellant signed a guarantee dated 18 September 2009, which on its face stated her liability as "UNLIMITED" for all present and future debts of DUNLETH. On 21 October 2009, she also registered a deed of hypothecation over her property (Stand 156 Groombridge) limiting her liability in respect of that security to US$150,000. When DUNLETH defaulted, the respondent sued for US$685,442.46. The other defendants did not defend, but the appellant defended on three grounds: (1) the word "UNLIMITED" was not in the guarantee when she signed it, so she was only liable for US$150,000; (2) the deed of hypothecation limited her liability to US$150,000; and (3) payments by other defendants exceeding US$150,000 had extinguished her liability.