As suggested in my answer to the previous question. "Afianzadora" could be "surety company" or "bonding company"; any of these expressions would be correct. A guarantor can be a (natural) person or an entity (a company); in this case it's the latter.

"A surety, surety bond or guaranty, in finance, is a promise by one party to assume responsibility for the debt obligation of a borrower if that borrower defaults. The person or company that provides this promise, is also known as a surety or guarantor."
http://en.wikipedia.org/wiki/Surety

http://www.proz.com/kudoz/spanish_to_english/finance_general...

("Cause" is unidiomatic here, in my opinion. What this means is that the supplier assumes responsibility for the guarantor establishing the waiver; if the guarantor fails to establish the waiver, the supplier shall be in breach of this undertaking.)