Until it is exchanged there is no agreement and you cannot enforce anything. Once exchanged the seller cannot back out. Only if the contract is subject to finance and/or building and pest reports, you can pull out if you are not happy with the reports or the finance falls through.
You should chase up the agent to see what is going on.
If the agent is telling you others are interested they want you to increase your offer.
There is no contract binding on the seller until they sign and the contract is exchanged.
If you think the agent has acted inappropriately you can report them but there is very little else you can do.
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