rw950431 on Undefined operator '>' for input arguments of type 'cell'.

I have the following code in a matlab visualisation which used to work fine. However in the last few days the data source has had problems and now my matlab code complains "Undefined operator '>' for input arguments of type 'cell'."

readChannelID = [150393];

%% Read Data %%

% Read first data variable
power = thingSpeakRead(readChannelID, 'OutputFormat','table' , 'NumDays', 3)

%% Visualize Data %%
dates=datenum(power.Timestamps);
price=power.Price
price(price>2000)=2000

  '-4e-05'
    '0.00014'
    '0.00014'
    '0.00014'
    '0.00014'
    '0.00014'
    '-3e-05'
    '6e-05'

Undefined operator '>' for input arguments of type cell.

I'm guessing it doesnt like the "-4e-05" type of entry.  If I reduce the time period to exclude these values it runs OK.

What can I do to clean my data so this works properly?