UPDATE:
Just received a mail from agent which was a direct reply to my withdrawal of original offer.
She says the Whatsapp messages from the sellers confirming they accept the higher amount is enough evidence/confirmation of offer.
Then she follows up by saying she is going to forward us Page 3 of the original OTP to fully sign again next to OUR amended amount. And in her words... "Then that will make the deal final and the sellers cannot change their minds again." Erm... not exactly OUR offer, but okay.
She wants us to fully sign, scan and return the document to her immediately. She says, and I quote.... "Then I will take it to the sellers tomorrow to sign the counter offer"
In the next mail she attaches the amended page 3 of the original OTP with the amended amount.
She again says we must both sign fully next to the changes and then says: "THIS COUNTER OFFER WAS IN PLACE SINCE 18H00 LAST NIGHT"
On the attached document the original purchase price is scratched out and changed to the higher amount, as well as the amount we will be applying for for a bond.
Only her full signature is next to both amendments.
Again asking for us to immediately sign and send it back to her.