For product they need to try make their brand into a positive one, pretty sure their brand image has been tarnished due to their terrible running of the business. They need to also improve on the intangible benefits (services) of their product because as you can see their getting a shit load of complaints, need to improve on their service.
Obviously they need to re-promote their business again, so I guess you can use advertising through mass media (they probably can afford it since it says it's a large business), though also, maybe they can implement some form of relationship marketing such as a loyalty card, spend this much and get this shit for free. Sales promotion may be needed to encourage first buyers to come due to coupons, refunds, discounts, shit like that.
Price maybe they should use price penetration to entice more customers and regain market share again due to increased competition.
If there's increasing inventories there's obvs some shit wrong with its distribution channels (Probably because of the external changes), an alteration may be required such as reducing the amount of supply from the producer.
