I have MasterCard for over 19 years & I never failed to make a payment on time. I have my checking account linked to make automatic minimum payment.

They even kept on raising my Credit limit without me asking for it until about 2 years ago to $20,000.00. I hardly ever use my card for large purchses.

For last 2 years I have been purchasing some big ticket items & I owe them over $17,000.00. I still have $3000.00 to borrow if I want to.

I recently asked them if they would raise my credit limit to $30,000.00 & they asked me what my income was & I told them $10,000.00 because I am now retired.

So instead of raising my limit they raised my minimum payment from $260.00 to $460.00.

Now I am afraid that if I pay them off total $16000.00 that I owe them or even pay say P00 or $10,000,00 they might further lower my credit which I don't want.

So how does this work & should I pay them more than minimum payment & if I did can they lower my credit limit further ?

Your minimum was raised because of your low income.
I can't believe you have only been paying the minimum all these years. Credit card rates are usery rates, often around 20% when a typical mortgage is 4.5% and bank interest is paying almost nothing.
In fact because of so many people owing so much, in recent years card companies have raised minimums for everyone.
I would find some free financial advisor somewhere, like AARP.
You might want to even transfer your card debt to another card if they offer you 6 months or a year of no interest, and STOP SPENDING. This is serious. If you have any savings or a 401K or IRA you can start using, use it to pay down this debt!

I didn't know that Ican transfer my debt to another card.

Also why would another card company take over such a huge debt knowing my income is so low ?

Also what would happen to my credit if I did that ?

Is it possible to ask the current Card company to lower my minimum payment & if yes would they do it & why ?

Can I be blunt & tell them that if they don't lower my minimum payment I might have to stop paying them completely ?

Many cards offer balance transfer deals. So if you had another card, you could transfer and usually get a much lower interest rate for a time.

You can try to negotiate a lower payment, but look at it from their angle. You are retired which means a lower income. You very recently built up your balance and asked for more credit, that you apparently cannot pay for. Being retired also indicates an advanced age, which means you may not live long enough to pay the balance at a lower payment. So I would doubt if they would negotiate unless you can prove you can pay the bill.

I suspect you have assets that allow you to pay the bills. I suggest you use those assets to get additional credit to use instead.

Being 'blunt' won't get you anywhere.
Apply for some of those free balance transfer/no interest for a year cards and I won't suggest that you maybe double-fudge your income, but some people do.
What I might do meanwhile is call your card co and ask for a trade: they lower your spending limit to 600/mo for 5 years and lower your minimum to 330/mo. You are unrealistic about how long it will take to pay this off at this rate, basically past your lifetime, because of accruing interest. 330/mo will take 12 years just to pay off the 18,000 you are behind, never mind what you need to pay for new each month.
You are also unrealistic about how much you need to curb your spending.
If you have to live on 10,000 income you are in big trouble, and it's time to start selling some of those big ticket items you bought recently.
Try to find family who want to lend you 18,000 at 5% instead, with automatic withdrawal, and pay back the card NOW.

I just noticed that you imply that you can pay them... which of course you will, if you have good financial sense.

A loan of 18,000 at 20% for 12 years is 330.59/mo for a total of 47,604.89
A loan of 18,000 at 20% for 31 years is 300.64/mo for a total of 111,838.87
You'll be dead before it's paid.
Can you see how absurd it is to continue this, for them and for you?