Complaint Review: Dell Inc

It is related to refund issue i have with Dell.com. I purchased Bose System worth $600+ tax from dell.com. I used my Credit card worth $250+tax and Dell Certificate from AMEX rewards worth $350 for the purchase of bose Sound system from Dell.com. I didnot like the product and i returned the bose sound system within 30 days return policy from dell. While returning, i called Dell Return customer specialist regarding my doubt on refund of my $350 used as Dell Coupon, which i receievd from AMEX, and also $250 used from my credit card while purchasing the bose system.Over the phone, the return specialist assured me that i will get refund of my amount whatever the mode of payment i made to purchase the bose product. Again, I did double check. while on the call with her, on my refund of my dell coupon used(specifically asked myself) she again assured me that yes u will get refund on coupon too. On that NOTE i agreed to return my product which i purchased from dell on the same call. I return my product using ups/fedex and reached dell address. After few days i called Dell Customer care to check the status of my refund, Dell Customer care started saying you have $250+tax refund waiting and will be refunded back to you once processed.Then i asked about dell coupon amount which return specialist assured me of refund while placing return oder. Then dell REP started saying dell coupons are not refunded and we will not refund and its lost.
If dell coupons are not refunded, why did return specialist lied me first in place, and falsely assured me of my full refund, when i called before initiate return of my bose product? Still Dell customer is not owning responsibility to cross check TRUTH and what myself and return specialist conversation had conversation and what false assurance provided by dell return specialist. Because of dell return specialist wrong information provided to me,I dont have my bose product or my $350 dell coupons issued by AMEX. Please help me resolve the issue. I have called dell customer care 100 times till now. sent messages over twitter, facebook but no resolution. Everytime they are saying coupons are not refunded. Issue here is when i called dell before initiating the return, why did return specialist provided FALSE/Wrong information? if she would have told me true and knowledgeable information, i would have not return my bose product?
Also one more important clause, if they say return policy with full refund. where is full refund here? Its fraud dell is involved in. I expect customer will call customer care to clarify but when customer in return gets wrong or misleading information, where shall the customer go?
I even tried contacting AMEX to re-issue coupons but amex declinded as they say they have issued one time and this problem belongs to dell and dell is liable for this mis-appropriate information provided to me.
Today i even got response over twitter regarding the same issue from dell customer specialist saying they dont have infomration about refund when i was placing an return request. if i go by that then why didn't return specialist bother to address upfront before initiating my return form over call?
Question here is about lies and avoidance to address the issue and punish the culprit lady from customer care.