Online holiday booking-misrepresentation,entitlement to refund.

[Aidron]

Hello,first time on a forum.apologies if post is overlong.Looking for any advice on where I stand,legally, after booking a holiday appt. in Spain, via the HomeAway UK website.Upon arrival at appt. building,was informed that it was overbooked,we were shown to a 2nd floor flat instead of stated "penthouse appt."with own private solarium and sea views, refused to accept this.Spoke to owner on phone,he admitted mistake but apart from staying in the 2nd floor flat,did not offer a suitable alternative.Could not reach HA UK customer support until the next day,as their phone lines were down due to "technical issues".In the meantime, booked overnight into a local hotel, then, using HA UK site, booked another appt. nearby for the duration of our 2wk break.HA customer support said they contacted owner, who admitted his mistake, said to supply bank details for refund,which we did through their website.Subsequently, received email from owner who stated, because of some spurious reasons he would not be refunding our money,seems that customer support are not being proactive in pursuing this[despite their Book With Confidence guarantee] and we have ended up paying for 2 appts.,as well as a hotel stay and 2 wasted days of our break [ps have used HA 3 times prior to this and never had any problems].Any advice on how to pursue this,even just for a point of principal?Thanks.