MX6 doesnt climb walls

Good Day ,<br> <br> I have sent an online query and an email to the customer care department but noone has come back to me .. please dont give me the copy and past answer you are giving everyone.<br> <br> I purchased a MX8 some time back and I am pleased with it , my fathers pool cleaner died a couple of weeks ago and when he asked me for my recommendation on the zodiac , I told him he cant go wrong ... however he purchased a MX6 as his pool is small and is so un happy with the product , the cleaner does not want to climb the walls at all , I suggested that maybe his pump was old so he paid R3000 to get a new pump and the mx6 still does not want to know about the walls , even though there is plenty of suction power .... my father is a pensioner going on 70 and cant afford to now replace the new mx6 with another cleaner especially after having the pump replaced and now he is having to go and brush the walls everyday himself as your cleaner will not work, which is very unfair on a 70 year old man that just purchased a new pool cleaner to go and have to brush the pool. please can you help or must I rather go to the media .<br>