Definitely complain - this is outrageous behaviour.
I had a dispute over fees with my solicitor not long ago and he was very rude to me.
An estimate of costs was made before commencing the case after our initial meeting, and i decided to proceed on the basis of the estimate. The case proceeded with no revisions of the initial estimate from the solicitor. Once the case was concluded the solicitor sent the final bill - which was double the original estimate, about £5k extra! 
A revised estimate equal to the final bill, dated the day before the bill, then arrived in the post the day after the actual bill! 
As I had only put aside the money to cover the original estimate, I had to approach the solicitor and ask to pay the extra £5k in instalments. I paid the amount of the original estimate immediately. He grudgingly agreed.
I then fell ill with a brain tumour and fell behind with the payments due to being unable to work (or walk, actually). I apologised to solicitor and asked for some time to catch up with the payments. he then threw a hissy fit, accused me of lying (er, what about the great big scar on the back of my head and letters from my consultant?) and insisted that i had to pay the whole amount "immediately" as "it was outrageous I was treating his firm like a bank"!
I also found out that he had retained money I had transferred to his client account over a year before to pay the barrister's fees, and was refusing to pay the barrister until i had paid his fees in full.
After getting further advice I was told that Law Society guidelines required a new cost estimate to be issued as soon as it is apparent to the solicitor that the final bill is likely to be significantly more than the original estimate. This had not been done. It is also highly unethical to hold client's money paid in for barrister's bills "hostage" against payment of their own bills.
I followed the firm's complaints procedure but sent my complaint to another partner in the firm as I had been treated so badly by this solicitor.
My complaint was dealt with very quickly by the other partner amd they agreed to refund the amount i had paid over the original estimate. If it had not been dealt with by them properly it would have been very easy to take the case to the Law Ombudsman.
I also had some email correspondence with the Law Ombudsman to get advice on how to proceed. They were very helpful and responded to my queries very promptly.
Don't let your solicitor get away with this. His behaviour is outrageous.