Hard to believe you use and paid your own lawyer and still manage to get into this mess.

First thing, who owns the property now? You said the transfer consent has been approved.. meaning the land office approves the transfer of property from you to purchaser? But has the transfer been done? What are the terms of transfer in the agreement between you and purchaser? Surely there's a deadline to fully pay up the balance?

You can try the forum in hba.org.my, there's more expert there. Or realestate.com.my, forum there is getting bad but there might still be a couple of legal experts there.

Well in this case, it seems the purchaser has defaulted on payment and breached his/her part of the agreement which SHOULD then be null and void. Note I said should, check the content of the agreement to be sure.

You should get your lawyer to evict the purchaser asap on the ground they are trespassing illegally. If your lawyer cannot do the job then find another one who can. You'll probably need to file a civil suit to get rental payment. A competent lawyer should be able to advise you on this.

Note that you can make a complain to Bar Council if your lawyer is not doing his job properly causing you to suffer losses. I don't understand about the no action by your lawyer part. Go through the paper trail and find out if your lawyer is doing is job, or just purchaser not responding.