Bad service

I am not happy with thier service. I called last week looking for 185/60 R15; they said its R499 . When I came on saturday; they told me its full I must come during the week ; they will help me with same price. Today someone was assisting; he told me its R520 including balance. The guys when they about to put the tyres now they told me I must pay R699 per tyre. I had to pay an extra R400 which was not budgeted. Goodhope tyres Bergvliet