Landscaper Agreed Quote Now Disputing - Help Please

[Dorsetsherlo]

Wonder if anyone can advise us please? We appointed a local landscaper to build a new patio, pathway, lay new lawn as part of our house renovation after an extension. The landscaper visited the house a few times for measurements and discussions around what we were looking for. In April, we received a quote and we discussed changing some areas so the quote was resent - this quote was sent through a online quote/accounting software, auto overwriting the previous one. We read the summary and explanation and after clarifying if an item was included, we approved the quote at a greater value than the original quote. The landscaper has been back to site since, made drawings and showed samples for us to choose from. We paid a holding deposit of £900 for a start date in July. The start date has been pushed back a few times and eventually work started at the end of August. We have paid a further £2,600 for materials and the landscaper has been on site for 2 weeks. The issue is that today, he asked to speak to me and explained that the quote did not reflect what he had built so far. He had made an error with the quote and during his revision from the original discussion, although he summarised and explained the changes clearly, completed the drawings to reflect the new structure, he has now realised that he didn’t change his quote. He now requires an additional £2,700 for materials. After explaining this, he went on to say that all the work he has done so far, we had not paid for and he was working for nothing. He asked to leave site to go home to source cheaper materials and he would come back to us. We received the revised amount and phoned him to discuss, he acted in an irrational way and became very unstable. He stated that he would leave site and bill us for the work so far. We have tried to enter into fair and calm negotiations and finally he has agreed to come to site tomorrow to collect his equipment and discuss it. He is stating that he will give X amount as a gesture of goodwill again which he stated was offered, rescinded and then offered again as long as we agree to something or he states we are suspending the contract and he is leaving to do other work until we can pay him. The question is, has he breached the contract by changing the quote or stating it wasn’t right/accurate? He’s mentioned suing for loss of earning And for us breaking the contract. We are really stuck, not sure what to do at all. His actions make me so concerned of a rouge trader or unscrupulous person. Thank you, this is our first post on the forum.