Isn't Masterhaus near you? Its in the shopping complex on the dual carriageway from Sunny beach to the airport. When we have been shopping we found the prices cheaper further away from the resorts but the price of delivery over a longer distance often makes them the same price.
Xenioc (pronounced Helios) beside the Masterhaus Complex have a really big selection of all types of furniture including sofa beds and have next day delivery, possibly even same day if you order early morning. There's also I thinks it's Verona walking distance from NFC just up past the Karting and through next set of traffic lights on right hand side of main road.