Disgusting Service

After being a satisfied customer for many years I now find the level of service totally unacceptable.
12 days ago whilst trying to pay for my shopping in Waitrose I discovered that my card had been blocked for no apparent reason. I rang the customer service department who confirmed the account had been blocked but would not give me any information as to why and said I would just have to wait for a call from the investigation dept. I asked to speak to someone in the dept. and was told they only worked Monday to Friday.
On the following Monday I rang again asking to be put through to the investigation dept. and was told they didn't accept incoming calls. When I queried the delay in them ringing me back I was informed they had a big backlog of calls that they were working through and there was nothing else they could do for me.
After 12 days of waiting for a phone call I rang again and was once again told all I could do was wait and that I should hopefully receive a call within the next week or two. If it does take another two weeks that will be a month from the time of discovering my card had been blocked for no apparent reason.
This is not the level of service I expect from John Lewis and would definitely recommend anyone considering a John Lewis Partnership card to look elsewhere.