Tenancy question

k... we have what I HAVE to believe is THE sleaziest landlord in Dubai. The most recent thing is as follows: Compressor is gone on upstairs aircon and needs replacing. My husband, in the interest of getting it sorted asap and also of being genuinely nice, said he could have the aircon maintenance people from his work repair it so there would be no labour cost and it would only be the cost of the compressor which he believes the maintenance guy said is Dhs 700 but might have been Dhs 1700. According to the tenancy agreement, any repairs under Dhs 500 are our responsibility and anything over Dhs 500 is the landlord's responsibility.
So I tell the landlord all this and he insists he never remembers reading any such thing in the contract but is more than happy (because he's just all heart!!!) to pay half regardless of the amount... Dhs 700... Dhs 1700... he's happy to go halves.
EXCUSE ME!?
So I point out that the contract says that anything over Dhs500 is his responsibility. And I say this in such a way to suggest that surely he must have misunderstood something for him to think he is being generous by offering to go halves! But no. He continues to repeat his 'offer' and brushes off anything I say about contract or what-have-you.
Now, the problem is that I went to check the tenancy agreement just to be sure and yes, indeed, it does say that. BUT... it' on the back and he never freakin' signed the back!!
So, do we have ANY leg to stand on?
And if not, is there any rule (not in the contract) that governs who is responsible for what maintenance if the tenancy agreement doesn't cover that (or isn't signed)?
Also, much as I HATE knowing that this man benefits financially because we are in his house, I don't want to move. We've moved 3 times in as many years (country/city moves) and I just don't want to move again.
So, the next question is, can he refuse to renew the lease?
On the same unsigned back of the agreement it says that we and he have to give the other written notice two months before the end of the agreement if we don't want to renew. But again, he didn't sign!
Would very much appreciate any info anyone might have.
Will also call RERA in the morning but could do with any info anyone might have before that.
Thanks so much.