Northwestern Mutual Annuity Rip-off Milwaukee Nationwide

The Northwesern Mutual Differed Income Annuityy that was sold to me did not provide the ability to surrender the contract.  Two years into the contract the interest Northwestern Mutual is paying is much less than what the salesperson had indicated that would be paid.   I want to cancel the contract but I am being told by Northwestern Mutual that there is no means to surrender the contract and get my money refunded.    It is my understanding that reputible companies include surrender terms in their annuity contracts.