8ta / Telkom Mobile
TELKOM WILL NOT SWAP PRODUCT 4 DAYS AFTER PURCHASE

I bought a HUWEI E5331 MI-FI router from Telkom Mobile, Shop 117, Garden Route Mall, George on 8-09-2013.
After installing it on 12-09-2013 in my home, I discovered that it was too slow for my needs.
I returned it on 12-09-2013 to the same shop with the request that they swap it for me for a much more expensive Model E5776 and I was willing to pay in the difference in cost of some R1700. However Telkom Garden Route Mall refused my request on the grounds that they will not refund 3G products regardless of the consumer protection law.
Are Telkom within their rights of the Law?